Total Annihilation is a game like no other i've seen.
Sure, many people think its one of those easy, no thought, tactical game where you build your limit of units in an army, then attack the enemy base like a madman. If you do this in T.A., You will be greeted with the entire destruction of your battalion, and you are defenseless to kill the enemy Amphibious tanks rolling like thunder and shelling your base. This game takes a lot of thought and tactical strategy. It is also fun to blow stuff up.
With a great list of battle ready machines to choose from, you can play one skirmish for hours, or find out how to defeat the CORE, or ARM in campaign.
It has some drawbacks though. The graphics aren't the best, and sometimes the game locks up. It is an "old" game (Made in 1997) to some people seeing as we've advanced our technology so far in the past few years.
If you can find it in stores, or if you can find the new T.A. CORE Contingeny, buy it and see what it is like. You can also check out T.A. Kingdoms if you are into Medevil style games The music in the game is by far the most fitting for it, and it gives you a good background mood for conquering.
You can also check out Phoenix Worx for a multiplayer based game, or check out some mods for it, with completely new robots and buildings to choose from.
So if you are getting tired of playing starcraft, or some other game, check out Total Annihilation for some fun!