Honestly, I think I wasted my money on my G15. All these special features like the G-keys and LCD and I don't even use them. Any standard USB keyboard would have served me fine. It is a nice keyboard for those who make use of the G-keys though. The Windows key lockout is a nice feature too.
I had a Lachesis at one point (my poor friend is using it now) and it has it's ups and downs. the short tracking height is very short (when you lift the mouse up off the pad it stops tracking VERY soon) but it was kind of uncomfortable for me.
I'm currently using a Logitech G9, and I like it more compared to the Lachesis. It's easier to aim because of it's design, but that also means its for right-handers only. It has two interchangeable grips which means less problems for people with bigger or smaller hands. Tracking distance is considerably higher than the Lachesis, and it really bugged me when I first used the G9.
Another mouse worth looking into is the Steelseries Ikari Laser.