Now you have already one unit in your army and the rest looks pretty predictable, right?
Well, Stelek already posted his take on this list elsewhere, but the bottom line is that if you take 3x10 Sternguard with Combi-Meltas, put them in a Drop Pod, you're in real good shape.
Meltas were always good, but they're even better in 5e.
Here's the thing people miss: Lascannons aren't very good weapons
Well, let's not go crazy. They're still very useful weapons. The problem is that a big way to get them for cheap has gone away (for Space Marines) with the 6-man Las/
Plas, and even the Las Preds are upcosted (if I recall right).
The option I see a lot is to take 10
Tac Marines, a Rhino and Combat Squad them to get a 5 man shooty squad, and a 5 man fighty squad. Not the straightforward deal that the 6-man Las/
Plas was, but it still works.
Bottom line: 5 Marines with a Lascannon, sitting in cover, is still a good option.
I think the optimal configuration is probably 10 Sternguard + 6 Combi-Meltas + Drop Pod, ringing up at around, what, 315 points?
With the price on Combi-Meltas, I'd say more like 8 of them, or even 10.
Also, I'm looking at the possibility of taking 1 Meltagun. Hate to give up the Boltgun, but you don't want to totally lose anti-tank from the squad after it unloads its Combi-Meltas.