I've played quite a bit of C&CRA 2/YR (too much abbreviation?) but haven't really played any of the other first decade stuff. At one point, I found the first decade box set at Half Price Books for $8 but when I got home to install the games I found that it was just the bonus disc and some B-movie collection disc in the box. Obviously I returned the game.
They gave me a 15% off coupon for my next purchase, but I always get 10% off anyway, so it wasn't much of a consolation for driving to/from the store. I always check my discs from Half Price Books now.
I have been playing C&C 3 and its expansion. It's definitely faster and prettier than RE2 was, but I'm not sure I'd say it's a better game(still very fun though).