i reckon Lachesis is one of the best mouses i have ever used, but get this, i sold mine, to get a Microsoft sidewinder X8 and a Logitech MX600. anyhow, Naga is useless unless you play MMO's where in the case that you do, it can be very useful.
Razer aren't the only good mouse brand out there, btw..
Live near an aldi? up there they sell a gaming mouse similar to the Razer Deathadder, and yet its not a bad mouse from what i've heard, and it costs about $40-$50, if you wanna be stingy, money-wise.
logitech are still good for making mouses also, even though they've slowed production down theres a few good ones out there for gaming: M950, G500, G9X (ugly looking thing), MX518.
have a good shop before you buy anything! =D