2008 Imac vs 2011 macbook pro

Need someone more informed on these things then me to help out.

I currently use a 24 inch Imac 2.8Ghz 4 Gig Ram Intel 2 core duo 1tb - I mainly use it for Final cut basic editing - any hardcore graphics intensive after effects is done someplace else.

This machine is my first love its brilliant and has served me well BUT I'm thinking of getting something a little more portable - Macbook Pro

So my question is, If I were to but a 2nd hand (I.e - more in my budget) 1-2 year old Macbook pro will it stand up against my imac in terms of performance?

Ideally I'd like a machine that will perfom as well and which I could pick up at a moments notice while on the fly.