Wait... If you build your own computer... How does a mouse come with it?
but yes, not all mices are created equal, and depending on your grip style, types of games you play, and hand size, the perfect mouse is HIGHLY subjective.
Now according to your title you seem to want suggestions. But from the content of your first post it doesn't seem like so. So let me get you started looking.
First tell us what games you play, what's your grip style (look at the stickies on this forum) and qre there any buttons you require?
Some preliminary suggestions: Razer deathadder, Logitech G400, also check out their sites and other brands like Mionix, Steelseries, Roccat and thermaltake (there are tons more) answer my questions and then we can tailor our suggestions. Oh, and once you get a good mouse, you'll need a good mousepad
P.s. sorry for any typos, typing this on the phone.