I run E-UAE on my mac mini g4 with 1gb and is usable. Not like winuae on my athlon machine, but it performs well. I only tested so far my wb setup and amigasys, no games for now, but i think that it will run no problems. On a macbook alu, you should be fine with speed. I have also e-uae in my athlon box under ubuntu and it performs well. Giving that your macbook has a higher clockspeed and better processor than my athlon box i think you should be fine. Also don't forget to use hi-toro for gui, because it makes your life easier than messing with .uaerc config file by hand.
If need more help i'm sure that in this board you will get it, as it has solved me another problems with my miggies.
@Karlos I forgot to say that i have on both my systems(mac & pc) a resolution of 1280x1024 for workbench and never found any problem.
P.D: I forgot to congratulate wayne for the new look of the site, its amazing!. Keep up the good work!.