Didn't read through all this, so I'm sorry if some of these have already been covered. It should be noted that pretty much any mouse, beyond the basic specifications is just preference. Some features are expensive and unnecessary for some people, but literally make the mouse to others. Two major things to consider are, how the mouse feels in your grip and what you want for performance/features. Knowing these things are critical to getting a mouse that you will enjoy! Now with that nonsense aside, on to the mice!
I play a wide variety of games and I've owned and or used a variety of mice. If you like a palm grip and are looking for something more ergonomic you could try the Mionix Naos. The Razer Imperator and death adder are also excellent choices, both being solid and comfortable. It comes down to preference, if you want the extra sensitivity, the imperator is better for you. The imperator's side buttons can also slide forwards and back a bit if that's relevant for you. The death adder was a little more comfortable to palm(for me at least, the more sloped back was preferable), but that's opinion. Personally, I use a claw grip most of the time and a looser fingertip/claw cross in other games, and I found the adjustable side buttons to be a nice a feature. I also game between 4-5k+ dpi putting another mark in favour of the Imperator for me. Now that's more personal preference again, if you think that the additional performance/features are worth the expenditure(aka you plan to use them), then I think you'll enjoy the Imperator. If you game at a slightly lower DPI and use a consistent grip(and are happy with the position of the side buttons) then the Death Adder is cheaper and will be great for what you need it to do.
I also mentioned the mionix, it's very comfortable to hold and relax with, I think it would make an excellent palm/relaxed mouse grip, but again I don't own it, because I claw grip. The very advantages that make the mionix fantastic to palm; annoy the hell out of me with my claw grip. Other than that you could also try something like the logitech g500 which has adjustable weights, good performance, has a very decent form factor, and as I recall isn't overly expensive. My personal mouse of choice atm is the Saitek Cyborg R.A.T. 7. Yes its pricey, but the software is solid, it has a good list of features, very good performance, and is completely customizable allowing you to make the mouse comfortable for you.
I haven't used any of the CM storm mice, but I was very tempted. They do seem quite good and they get some pretty good reviews. I haven't even had the opportunity to see the corsair gaming mice in person, but the specs/look of them is solid, but I have heard that they are quite heavy. (if that's a factor for you) I have used ambidextrous mice before(Steelseries and razer), and while fine when I used to fingertip exclusively I have found that they are not particularly good for claw/palm grips. As usual with mice, its personal preference. If you like the grip with one of those then go for it, the performance is solid on most of them and their software feature line-ups tend to be good. That said they also tend to be missing things like extra buttons and customization options.
There are literally countless mice you could look for, but it comes down to picking what you need in a mouse. The level of sensitivity, customization, programmability, number of buttons, materials used, on the fly dpi or profile switching, weight and or adjustable weights, acceleration, price, other software and hardware flavours all determine what you need in a mouse. On top of all that you need to be comfortable with how you grip the mouse. So, my advice would be to pick out what you need in terms of features or performance and then look at the grip and feel of the mice that fit your preferences. If you can't find one that's comfortable in what you are looking for then you'll need to expand your selection by being more flexible and going from there(you could also change your grip, which is what I ended up doing at some point in the past, but that's neither here nor there).
I hope that was more helpful than it was annoying to get through. =P
Mouse History: Microsoft MX518 (I think is what it was), Razer Copperhead, Razer Lachesis, Steelseries Kana (briefly), Logitech G9, Razer Naga, Saitek Cyborg R.A.T. 7 Contagion (note this not entirely in order and as I said I've tried countless other mice[friends are gamers too!])
