Just curious as to what my fellow WoC players think the best missle/war machine killers are?

I have yet to try any of the units because I'm going to wait until the next year to start my army but was interested in using different units like Warhounds, MHorsemen, CChariots or CSpawn along side my warriors, or should I just armour-up, load up on magic, and get a Hellcannon?

Ahoy there.

For hunting down Warmachines, we don't have a ton of options. Being denied harpies hurts a bit.
However, Marauder horsemen as light cav./ vanguard as CORE is amazing. Give them some flails and throwing spears and you have a very good harrying unit that costs very little.
Warhounds are decent, but not that effective, even if they survive to get into combat. (which, they most often do not). They are very cheap and good as disposable units: setting up charges, taking some volleys, pulling fanatics etc.

Spawns are too pricey for their cost and cannot be relied on. On bad Movement roll, and you have a useless unit. Seeing that most units will outrank it, you lose out on much of it's potency.

Chariots are ok. Seeing as we're WoC and have VERY nice Initiative, we really don't need chariots. Their IMPACT hits is what make them useful. After their impact hits, they have very little staying power. Our Warriors are more potent and cheaper than the chariot (which is about 100is points...easily 5-8 warriors), they will work much better than the cumbersome chariot.
I use chariots w/ my beastmen as our I is low and they are CORE for us and 20+% cheaper than yours. So beastmen can field large amounts or many as flanking units.

Honestly, I'd try out some horsemen. They're cheap and if they die, you lost 80-100ish points. Couple them with some cheap hounds and you can cause some nice panic. Just don't take away from your main lines.

Double Hellcannons are a sight to see and can smash the living bejezus out of unsuspecting armies.

I am going to echo Blackspine on this one. Marauder Horsemen is the way to go for the WoC as far as a harrying unit or warmachine hunters. They are CORE which is nice that they don't take up space in those precious special and rare spots, and they are relatively points cost effective.

Magic and MoT

Maurder cav need to be lucky not to get shot by archers/ gunners on their way in, and their not durable. You'll therefore need to take a big unit (10ish) which is a bit pricy and unweildly

Hellcannons work if you every hit, but are not exactly reliable

Thanks guys, I'll deffinetly try to use the MHorsemen and Warhound combo. I had thought of using the horsemen with the MoS to run on the flanks. I was also wanting to use the hounds (mostly because they looked cool) but heard from many sources to not use them if at all possible because they are fragile/free points/not as fast as other choices.

The simplest solution to missile troops, in my experience, has been to trust in the armor of your Warriors (you're buying them shields, right? You've got a 3+ save against the majority of missile fire.) Those missile troops can't even begin to stand up to your Warriors in combat, so even if you get a depleted unit up into a gunline, you'll do horrible things to it.

War machines are a slightly different problem. As insane as this sounds... I ignore them. They earn their points back by killing some warriors. Good for them. However, the armies that rely on war machine fire typically don't do so well in close combat, and even depleted units will still power through combats. If you're really worried about it, however, using Warhounds as a physical screen (providing hard cover) for your expensive units works wonders. You only really need a unit of five models to do the job (a 30 point investment, at that), and it takes care of your bolt thrower woes.

I'd skip the hounds for war machines and go for the horsemen with flails and khorne. Khorne gives them frenzy which is quite handy. After all you do not want to put units of over 5 horsemen because they just cost to much. Frenzy gives immune to psychology, ideal for when you take some shooting hits. They only have ld 7.

And the extra attack is useful as well. Furthermore take note that when attacking a war machine it's like attacking a building. For a building you choose 10 models who fight. For a warmachine you choose 6, BUT cavalry models count as 3 models so that means only 2 horsemen will be able to attack. So you really want those 4 A instead of just 2 A. Your opponent will mostly get higher ground bonus which negates your charge, and if he gets lucky and kills one (which isn't that hard) he can even win or draw the combat. They're also stubborn (or so I think, could be that only the dwarfs are) so you'll want to kill them before breaking them. Otherwise your 105 pts (5 horsemen, flails and khorne) will be stuck. And when not, then mostly count on a general or bsb being near making it very hard to break them.

As for problems with shooting, I tend not to find much trouble with such armies. I do play with a big knight unit and a chaos lord on daemonic mount all of tzeentch, blasted standard and a wizard with the collar of khorne. This makes them almost immune to many things and they grind their way into combat. Now you do not need to do the same but next to that I play small warrior units of 10 man with halberds and Khorne ofc. These can fall pretty quickly from shooting (especially crossbows and DE repeaters with armour penetration). The thing is, people these days do not know what to expect from Chaos armies. We've gotten some very nasty surprises and the ability to create tons of lists which can all create havoc and mayhem. Use the knowledge of your army you have against your opponent and remember moving is your most important phase and you should be good against shooting. So where I'm going with this is, outmanoever your opponent even if he is a steady army that just shoots and shoots some more. Sometimes you need to put a point-filler unit to the front to take the brunt of shooting, sometimes it's more interesting to use a pricey unit to take the brunt but who will mostly survive. Don't run in blindly trusting on dice because sooner or later this will turn against you. Let some be the pincushions and some the hammer.

The main drawback of your Khornate M-Horsemen is that their frenzy robs them of the ability to bait the enemy. If you're not up against a gunline What do they do?

I've found that a unit of 5 with MoS, flails, throwing spears. light armor, and musician are a more versatile unit. They can still smack around war machines (you get 2 S5 attacks from the marauders and 2 S3 attacks from the horses...and everyone knows the dang horses do all the damage). At only 101 points (you can drop the light armor and make them under 100, but the extra AS is nice, especially as most warmachine crews are S3) they're not a big investment. The MoS allows them the benefits of ITP without the drawback of having to accept a charge. And it's half the cost of the MoK. You might not break warmachine crews as often, but if you tie them up in combat they ain't shooting. And with the insane charge ranges now available you don't need them tied up for long before you're stuck in and happy.

Well, I just don't use them as bait since to be honest every experienced player in warhammer no longer is easily baited by fast cav or skirmishers. When I'm not up against a gunline I manoeuver them so that they can easily take flanks and rears. You might think it is hard to keep them 20" away from enemy units but sometimes it is surprisingly easy and ofcourse that which you don't face, you can't charge. Make use of the reform rule and place them only within frenzy range when you intend to charge the next turn anyway. These riders of mine have quite taken some stuff away already as well as supported very nicely in multiple combats. It actually comes to the fact that frenzy is something you need to play with. It needs to be a toy in your hands and to be "abused" according to the rules. Keep calculation with your opponents movement and you're alright.