I hate the mighty mouse aswell... I was also of the idea of that nothing beats the trackpad, which is true, but i have an external monitor and I got the elevator stand, so I cant use my trackpad cause it is not within my reach.
So I started an intensive search for a good mouse. As I didnt want to fool around with dongles and stuff, I searched for bluetooth mice. Results:
Wireless Mighty Mouse
Microsoft Laser Mouse 5000
Logitech V470 (I think)
Some keningston mice
some other.
Problems I found, the mighty mouse has horrible reviews plus I disliked its tracking.
The MS mouse is ok, but it is too small for me, I have large fingers and as I wanted it for my desk it is very uncomfortable, I wouldn't mind if it was an on-the-go mouse.
Logitech V470 seems good, has good reviews but it has little functionality... so it was a turn off for me. And as someone commented, the trackpad is awesome, so I needed something to match its functionality.
So i noticed the MX Revolution which is a pricey mouse but it feels smooth, and it is awesome. If you pair it with the Steermouse app, you can configure it to do the same things as the trackpad. In my case, with the multiclutch app, i open, close tabs, cycle through them, expose, and more.
However, for me i didnt want a dongle.... So i noticed that logitech sells a set called MX5500 which includes the MX Revolution in a bluetooth version, and a keyboard. Both bluetooth, yet no Mac support. After looking around, I see that it works, btu there is no support from logitech, so you need to use this apps. I ended up paying a lot, but I love this mouse. The tracking is soooooo smooth and beats the MM hands down. It feels confortable on hand and using it is the next best thing to using the trackpad. So I ended up paying a lot, but for me it was worth it.
However, if the dongle is not a problem from you, the MX Revoluion in the standard version is the a good choice, but for 30 bucks more (in amazon) you can get the MX5500 kit.
I would recommend using steermouse to see waht functionality it adds to an external mouse.
And fyi, amazon sells refurbished versions of the MX5500 for a very low price, around 70 or something like that. So it might be worth giving it a try.
Good luck