HQ
Librarian - Null Zone, Gate (100)
Elite
Dreadnought - x2 TLAC (125)
Dreadnought - x2 TLAC (125)
Ironclad Dreadnought - Drop Pod (170)
Troops
Tactical Squad x10 - Melta, Missile Launcher, Razorback (215)
Tactical Squad x10 - Melta, Missile Launcher, Razorback (215)
Tactical Squad x10 - Flamer, Missile Launcher, Razorback (210)
Scouts x5 - x4 Sniper Rifles, Combi-melta, Missile Launcher, Camo Cloaks (100)
Scouts x5 - x4 Sniper Rifles, Combi-melta, Missile Launcher, Camo Cloaks (100)
Fast Attack
Land Speeder Squadron x2 - x1 Multi-melta each (120)
Land Speeder Squadron x2 - x1 Multi-melta each (120)
Land Speeder Squadron x2 (100)
Heavy Support
Thunderfire Cannon (100)
Thunderfire Cannon (100)
Thunderfire Cannon (100)
2000 total points.
I'll segment my post by FOC slot. First off is the Libby.
Libby seems to be pretty good, although I question the usage of GoI, since IDK how, who, or what you're running him with. Otherwise, Null is always a good choice, especially against your former Army. (Poor Daemons...)
Troops:
(I'll start with the Tac Squads, seeing as how they're the bread and butter of any Nilla Wafer SM list)
Your Tac Squads are chosen pretty well, and seeing that you have plenty of Dakka not only on the normal Bolterbacks, but in the Tac Squad itself, however, the Meltagun in squads 1 and 2 are *somewhat* questionable, lots emphasis on somewhat. Combat Squadding the M.L. is always a good idea, gives your M.L. a good shot at shooting important things like AV13 and lower and shooting MCs.
Onto the Scouts, which is where I see somewhat of a problem:
Scouts x5 - x4 Sniper Rifles, Combi-melta, Missile Launcher, Camo Cloaks
This Combi-Melta. It really doesn't mesh together well with the rest of the squad, considering you can only pop it at 12in or less, and you'd want to be within assault range to make it even more killy, which clashes with your Snipers' 36" and your M.L.s' 48". You should probably drop it, it'd be a good point saver.
Elites:
Riflemen Dreads, good choice, always good as a Transport buster, and seeing your units are going to get up close and personal, it indeed does synergize well. The Ironclad that DPs, that's going to be vverrryyy annoying for them. I've never actually ran one of them, so when you do play with it, tell me how it goes, I'd like to hear how effective they are.
Fast Attack:
This is where it gets kinda odd.
For your 4 Melta Land Speeders, you're taking 2 in a squad in 2 separate slots and taking 1 Multi-Melta on one of them, but you're pricing it for 120. I might need some more explanation on that one, since you should be paying just 110 for one Force Org. Slot. The two plain Land Speeders are questionable too, since you can make them a whole lot more killyer than just Hvy. Bolters.
Heavy Support:
AWW YEAH THUNDERFIRE CANNONS. I've only seen one person run them, which is disappointing, since they seem pretty sweet and tougher, especially since you're Bolstering Defense with the Tech Marines. Tell me how these go too.
Conclusion:
All in all, this is a good list, with some questionable decisions, but otherwise good.