That FPS was C&C: Renegade, and I absolutely enjoyed it too. It had all the cheesy dialogue and cliché elements that kinda gave C&C an 80s action movie flick flair, and I was really disappointed that it wasn't so successful. I think that the multiplayer parts weren't really refined enough to make it a hit... there was too much "base-building-components" for an MP game, I think they should've went with a "Battlefield 1942"-style of gameplay... holy crap, now that would've been awesome! EDIT: They were released around the same time, so there wasn't any blueprint for the BF1942 style of gameplay around at the time. I think making vehicles spawn for everyone and not tying it to your success is part of what made BF1942 so popular in the day.
Of all the RTS games from C&C, RA2 was my favorite. Tiberium Sun was just a stone throw before my time, so when I played it, I was missing all the new elements from RA2. It's no fault of TS, just that I have already been "spoilt" by that time...
Tiberium Wars was also pretty nice, though I only played some LAN skirmishes with friends, never the campaign. But from the looks of things, it was the last "real" RTS in the C&C series. The latest two RTS installments, RA3 and the last Tiberium one, already forgot what it's called, were just trash, IMHO. In the latter, the publisher (EA?) was obviously trying to kill two birds with one stone, i.e. make a game for both PC and mobile markets, and C&C was the guinea pig brought in. Obviously, the publisher had no idea what C&C is about and where its true value lies. That's some pretty bad management, actually, but that publisher is known for treating their consumers like replaceable goods, completely neglecting any artistic value a game might have and the therefore resulting fan-base/community like consumer-behaviour.