Saving this topic. My Razer is dying ...

Personally I've been using Logitech MX500 -> MX518 -> G500. They all still work, but the first two's exterior was just wearing out from years of usage and felt uncomfortable for prolonged use. The G500 feels a little heavy for me, but nothing else came close that fit my budget and needs. 3 buttons on the side and they're not in the way or hard to reach, plus it's got tilt scrolling for 2 extra buttons in games. The mouse wheel can switch to fast scrolling for long documents or click scrolling with a switch for something a little more precise. I rarely use the adjustable dpi, but it's handy on rare occassions.

My current mouse is a Logitech MX620. When that gives out, I'll probably get a or a [url=http://www.logitech.com/en-us/mice-pointers/mice/devices/performance-mouse-mx]Performance Mouse MX. Once I got used to being able to switch between geared and frictionless running of the mouse wheel, I never wanted to be without that function again.

Left, Right, and scroll wheel. I don't like mice with side buttons because I always accidentally bump them.

Razer Naga /Mamba
Why? Because they are amazing ;)

These are what I use at home, at work I use a Microsoft Trackball Explorer 1.0 (attached) that no one else wanted but I think is quite awesome (and as an added bonus, they can't quite comprehend how to use my computer due to them being used to normal mice, and possibly laptop touchpads). The M705 is just a little too small in my opinion.

Razer Impreator. It loves my hand dearly.

Also, I'd like to add that I used this thing (Cyborg RAT7) for a while. It's nice, adaptability and button placement wise, but it tilted too much and almost sprained my wrist... for some reason.

If you like the MX518, I'd recommend the G400 which is the remake.

Going to buy it for myself in a week so can give feedback then!
My G500 just started failing, but it served me well for a good 5 years.
As for the G5, personally I found it too heavy.

edit: currently using the G9x as a replacement mouse. It's not bad, but it's too small for my hand.

Razer Death Adder Left Handed Edition, because it's completely awesome, and the only ergonomic left handed gaming mouse I'm aware of.

If Razer were to make a left handed version of the Naga, my life would be complete...

The cheapest thing Microsoft makes. I'm willing to pay a lot for a good keyboard, but never really saw a reason to invest too much in a mouse. And Microsoft's entry-level peripherals are quite well made, considering how cheap they are.

seconded. razer has stellar ergonomics and style, and they often don't cost too much. just keep track of that warranty, i've had several fail (majority were refurbs)

The cheapest simplest logitech. A little more money and they feel obliged to add ergonomic design features and extra buttons making the mouse awkward to use.

I do have a bit more expensive laser thingy at my gaming PC, no difference.

Logitech MX518 -> G400, such a great line they keep remaking it for years now.

you can get tech stats and reliability reviews from us, but you should probably go to a best buy or fry's or something and hold a few in your hand. you are going to use this thing for thousands of hours, it should feel right for you