HQ:
Company Master-115 pts
Power Weapon
Looking pretty good, if you have a few spare points then might I suggest swapping the company masters power weapon out for a lightning claw? (Or a pair if you have a few more points on top of those spare points; an extra shot can be cool, but a pair of claws retains that power weapons extra attack along with the lightning claw re-roll buff.)
Command Squad-170 pts
Company Master
Power Weapon
Plasma gun
Melta gun
-Rhino-35 pts
Is that company master supposed to be company champion? It confused me at first, because the master is four times the cost of the champion and all that.
Dark Angels are very well known for being able to make use of a higher volume of plasma weaponry fluffwise, but in this list I would very much advise against it. Plasmaguns are both expensive, and rapid fire; that first one means less points to spend elsewhere, and the second means that if it shoots, no charge for the squad and the company champion is wasted.
I would suggest either swapping out for a second meltagun (redundancy never hurt chances of doing damage) or trading the second special weapon in for an apothecary to give the squad feel no pain. He would cost you a few more points, but is definitely worth it to increase their survivability.
Elites:
(5)Scout Squad-125 pts
4 Sniper Rifles
Missile Launcher
I rather like sniper scouts with an attached missile launcher, dislike that you have to pay for the rifles (these guys are already stealing an elite slot!)
However it does look like you are paying to much for the squad, four sniper rifles and one missile launcher should come out to half the total points of the base squad, meaning your paying 120 points, not 125. (Hey look at that, actually squeezed some points out of this list.)
Troops:
(10)Tac Squad-175 pts
Multi-melta
-Rhino-35 pts
(10)Tac Squad-175 pts
Multi-melta
-Rhino-35 pts
(10)Tac Squad-175 pts
Multi-melta
-Rhino-35 pts
Personally, while these three squads do give you bodies there is not a whole lot you can do with them. I would very much advise replacing them with four five man squads armed with power weapons, meltabombs, and flamers or with meltaguns and powerfists.
If you did that, I would suggest the following:
2x Tactical squad
Meltagun; powerfist; razorback
175
2x Tactical squad
Flamer; power weapon; meltabombs; rhino
150
Comes out to 650 points total, which is slightly more than your 630, but you have four squads, and four vehicles (two of which have heavy weapons they can make use of.)
The biggest problem Dark Angels suffer over other marine codecies right now is the points they have to pay for everything. Nothing is free, and most things are overpriced in comparison.
Fast Attack:
Ravenwing Bikers-195 pts
Attack bike w/ Multi-melta
2 Melta guns
Melta bombs
Ravenwing Bikers-195 pts
Attack bike w/ Multi-melta
2 Melta guns
Melta bombs
Like these squads, maybe ditch the meltabombs for the points to use elsewhere?
(2)Ravenwing Landspeeders-150 pts
2 Heavy Flamers
2 Heavy Bolters
Like these two, wouldn't change anything
Heavy Support:
Devastator Squad-190 pts
4 Plasma cannons
Devastator Squad-150 pts
4 Heavy Bolters
These two squads I would suggest losing a heavy weapon each. Four big guns means a lot of potential kills, but at five strong you don't have many ablative wounds before you risk losing those guns. Two bolter bodies is better than a single one, plus would give you forty points to spend elsewhere and make any of the possible alterations I suggested before.
Predator-95 pts
Heavy Bolter side sponsons
Like this, would not change it; though it does suffer from overpriced as I mentioned before.
Whoa wait a second..
HQ: 320
Elites: 120
Troops: 630
Fast Attack: 540
Heavy Support: 435
Total: 2045
Way over 1850, something needs to go (losing a biker squad actually brings you down to 1850 on the dot.) I personally would suggest ditching the command squad; your total drops to 1840 and you have a few more points to work with.