All of them mate - a good pack would be themed (like suburbian
) - and have a few characters, a few weapons, and the blocks to make the level out of. For the people using FPSC I think that they'd like to be able to set the theme properly, so lot of textures and a decent selection of wall and roof bits would be great - you could probably recycle a lot of your older textures. A general woman and man model for instance would be cool - people could easily skin the characters to look like their friends or whatever, that and maybe a fireman and policeman would be pretty nice - it'd get the idea juice flowing and people will need your pack. Just remember to keep the price nice and low, there's plenty sales to be had so a lower price might help as most FPSC'ers are probably on pocket money.
Even if TGC don't want to sell your pack, you could sell it yourself through paypal - but from the quality you've shown I've no idea why they would'nt want to help. After all, the more stuff available for FPSC the better for TGC.
Van-B
Put away, those fiery biscuits!