Over eight years of playing, I've found a couple things. First, tanks rarely make up the majority of your opponent's points, so it doesn't necessarily make sense to bring the majority of your points to combat them. Second, there's very little you can't accomplish by being tactically flexible with your units. Rather than gear them towards specific tasks, making sure the unit has something, even if it's just krak grenades, to deal with armour if you need them to. I rarely take anti tank weapons in my armies purely for the task of dealing with armour-- the exception is that I'm quite fond of the Predator Annihilator with heavy bolter sponsons, since it's mobile. I lean pretty heavily on meltaguns. A lot of people think of meltas as anti-tank weapons, and I suppose they technically are, but S8 AP1 works just fine against...well...anything. When you're packing boltguns these days, the 12'' range isn't quite what I'd call inhibitive, and if you're playing Blood Angels, you're wanting to get stuck in anyway so range (or lack thereof) shouldn't be a major consideration. Now that I really think about it, I lean more heavily on meltaguns than I do on almost any other non-standard-issue weapon in the game, purely because you can do anything you need with it.
Similarly, I tend to take missile launchers or heavy bolters in infantry squads that have heavy weapons. Missiles are quite flexible--don't write off frag missiles completely, because you can get a fair few number of models with 'em, and you'd be surprised what they do to Terminators. More reliable to shoot a terminator squad with a frag missile than a krak missile, oddly enough. Now, you're probably asking why I mentioned the heavy bolter. Against skimmers, you're better off with higher numbers of shots that only glance at best anyway. You ultimately end up with more chances to do damage with a heavy bolter against something like a land speeder or the like than you are with a lascannon. Yes, generally speaking, you'll use the heavy bolter against enemy infantry-- that's what it's really there for-- but you'd be surprised what you can do with it in a pinch. In my opinion, heavy bolters are the most under-points heavy weapons in the game-- five points in Codex: Space Marines. They're more appropriately priced in the Angel Codecies, I think, since they make such a mess of anything not in power armour. And let's be honest... there's a hell of a lot out there that doesn't have a 3+ armor save. Best weapon for fighting Tau to boot, I think... kills 'em on 2's, and outranges pulse rifles.
