Can anyone recommend a good eyeshadow base?

I've never tried it, but Urban Decay Primer Potion gets really great reviews. I use Smashbox lip primer. Just a smidge on the lid gets me a nice clean base. I tried MAC bare canvas, but it's a little too light for me.
 
I use the Urban Decay and the MAC primer , The Urban Decay is the Best eyeshadow base I have ever used , even the lighest sheerest colors look virbrant on your skin , the MAC you can get in differnt shades , which I like too , hope this helps !
 
I agree that F.Y. Eye is the best. I use it when I go clubbing and it really makes my make-up stay on even after sweating on the dance floor for hours. It's also great for weddings or other formal events where you want your make-up to stay put. You only need a little bit and the jar lasts forever!

i third FYEYE by benefit! i have oily eyelids and use it EVERYDAY.