I bought a refurb 17" rev B. imac (2 GHz/superdrive) for $949 from the Special Deals page on store.apple.com, then bought a nice external 19" LCD (LG 1930B) for $300. Total price: $1249, less than a new 17" or refurb rev B 20" - and with way more screen space than either, thanks to the screen-spanning patch.
Once you go dual-monitor, you'll never go back to anything smaller than the 30" ACD, trust me.
I bought a refurb 17" rev B. imac (2 GHz/superdrive) for $949 from the Special Deals page on store.apple.com, then bought a nice external 19" LCD (LG 1930B) for $300. Total price: $1249, less than a new 17" or refurb rev B 20" - and with way more screen space than either, thanks to the screen-spanning patch.
Once you go dual-monitor, you'll never go back to anything smaller than the 30" ACD, trust me.
The dual monitor idea sounds good if you feel that you would need/want the space. If you want to stick with one monitor, go for the 20" unless you plan to use the iSight and the remote with Front Row.