If anyone here is looking for a new game to play, have you tried Battlezone?  It's an amazing game from 98.  It's a combination tank shooter/RTS.  You pilot a tank, and can take on your enemies yourself, but you also control your units - tell your recycler to build scavangers, constructors, and factories which build better units.  I'd highly suggest trying out the game.  It's got a great storyline, too.

It doesn't normally work on XP, but you can now download Battlezone Enhanced for free, which has many improvements, including working on XP.  The only downside is that BZE doesn't have singleplayer.

Check out BZE here: http://www.battlezoneclub.org/forum/

If you want the singleplayer game, you can download that as well, but I'd reccomend against playing multiplayer in this version, as it's highly hackable: http://battlezone1.freeforums.org/downloads-bz-1-4o-installer-t12.html

Come to the Battlezone Club forum (the first link).  Everyone there is very helpful.

EDIT-- Also, if you're interested, there's also a sequel called (oddly enough) Battlezone 2.  It has its strengths and weaknesses.  Better interface, but the single-player campaign missions aren't very well done.  They have a good storyline, but not much base-buiding.  If you get BZ2, make sure you download the 1.2 patch, and the VERY well done mod Forgotten Enemies.  I swear, if you didn't know Forgotten Enemies was a community made mod, you'd think it was a proffesionally done expansion.  Well done story missions, good voice-overs, good maps, well-designed ships.

You can buy BZ2 used for as cheap as 5-10 dollars on Amazon.  Check it out.