Command & Conquer is one of those series that'll always grab my attention. After being introduced to the series with Red Alert on PS1 (RTS with a playstation 1 pad is not the ideal experience though), I fell in love with Red Alert 2 and Tiberian Sun on PC. The series oozes personality and the core gameplay loop of gathering resources and building your base is near-perfect in many C&C games. Red Alert 2 is a classic in many regards, and is probably the C&C most people remember, but I feel like the mechanically best game in the series is Generals, even though I've put in more hours in RA2.

I absolutely love how the three factions in Generals work, how they all have fundamentally different strengths and gathering mechanics; USA is slow, powerful and expensive, China is inexpensive but relies on bonuses gained from having large numbers of troop in near vicinities of each other, and GLA (a terrorist faction) focuses on hit 'n run tactics and subversion, avoiding head on attacks. The game is probably hugely unbalanced seen in retrospect but it made for a seriously entertaining game, when every faction is so unique.

After Generals though, my interest waned a bit. RA3 never really seemed like anything special, and it felt like the franchise had peaked with RA2/Tiberian Sun/Generals.

I really hope for a return of the series at some point - until then, I highly recommend keeping an eye on /r/openRA, a project for an open source rebuild of the classic 2D games (+ Dune, another Westwood game). There's working builds of several games and an active multiplayer scene, which only seems to grow larger as more features are introduced.