I'd take Ratlings for snipers.
Also, with that much infantry a company command squad would be a good investment. First Rank Fire, Second Rank Fire is really awesome.
First Rank Fire, Second Rank Fire is only really good when you have a full 50 troops in a combined squad, although it'd be almost impossible to get them all in range under normal circumstances. I built a 1000 point army around that idea, and it fared okay, though it was mostly the heavy weapon squads that did the bruising, while the combined five infantry squad mostly just died horribly to a dreadnought (hilarious because my opponent sacrificed a venerable dreadnought to devastate them, which did exactly jack shit to hurt my damage capability (after all, he wasn't in a position to exploit the weakpoint that put in my defenses; the squad didn't have the range to hit his marines hiding on the other side of the map, but would have devastated them if they tried charging down the middle (which led to him trying to run a rhino down the sidelines, where it was shredded by a lascannon because derp)); I think it was a vet-squad with a heavy flamer than did it in, blasting its rear armor, getting an "explodes!" result (meaning I got lucky as hell, rolling two sixes against it, although a wrecked result would have been better...), killing about a dozen of the main infantry squad...
).
IG: 1000
Company Command Squad +50: 65
-Mortar +5
-Grenade Launcher +5x2
Platoon Command Squad +30: 35
-Vox-caster +5
Infantry Squad +50x5: 365
-Vox-caster +5
-Commissar +35
-Grenade Launcher +5x5
-Autocannon +10x5
Heavy Weapons Squad +60x5: 435
-Heavy Bolter +5x9
-Lascannon +15x6
Veteran Squad +70:
-Heavy Flamer +20
-Flamer +5x2
Done right, it creates a very bad situation for your opponent: stay bunkered down, getting chipped away at by the heavy weapon teams, or charge, and get torn up the heavy weapon teams and a potential
100-150 lasgun shots if within a good chunk of the map. If I were to throw in some good artillery and a bit of armor to shore up the ranks, it would be even nastier...