I really enjoyed the novel and have played both of the xBox renditions (I agree with everyone else in that the first one was quite nasty).
For figures, I'm collecting the aforementioned Lead Adventure range and augmenting it with Copplestone Castings' Future Wars neo-sovs, partisans and scavengers (as you can see in a recent post of mine). I'm also adding Pig Iron's Kolony stuff (their Ferals, Militia and Rebels). In the end I'd like each faction to have a distinctive 'look' about them.
For rules, I'm thinking of modifying 'Skirmish Sangin' (for detail) or 'Space Hulk' (for easy mayhem). But these are just concepts right now. I've heard good things about Two Hour Wargames' 'After the Horsemen' but I've not actually read the rules yet...
I hope this helps somewhat!
Curt