Use regular mouse with Lion?

Yup. you can use Hot corners to map a corner to a "gesture" action

 

Not only that, but you can map (some) key combinations to things like Mission Control, or use dock icons.

I currently use Lion with my non-multitouch trackpad and a Mighty Mouse, but I'm currently awaiting delivery of a nice Microsoft mouse as I am frankly sick of the Mighty Mouse's flaws (trackball, poor left/middle/right click detection, poor battery life with NiMH AAs).

 

I use a Cyborg RAT 5 mouse with my Mac Mini and it works really well. It helps that MadCatz just released Mac drivers, which gives me all the functionality of the mouse (it didn't function at all with a Mac before).

I have Lion on my MBP and the Mini and the experiences are varied. I think a normal mouse works just fine with a combination of key combinations as well. Some on here recommend using hot corners, which is decent advice. Personally, I've never liked hot corners, because I take my cursor all over the screen and hate it when I accidentally activate a hot corner. I don't keep Launchpad or Mission Control in my dock and I still find it easy to get to. I've mapped Launchpad to F13 and Mission Control to F10. F11 shows the desktop and F9 shows the windows within an open program. That works the best for me. The only thing I wish I could do is scroll between spaces easily. As it is, I just use Control-Arrows.

Hope that helps!