Recommendations for purchasing low cost but Powerful Macs I've started to a lot of video editing with Adobe Premiere CS5 and After Effects CS5. I don't really have the money for a new Mac Pro. I feel that laptops are general underpowered and I have no need to be mobile.

Where should I look for low cost Intel Macs that fit my needs? In general, I don't think refurbished Macs from Apple are low cost.
How do you feel about a used machine? A one or two year old Mac Pro tower is still a very nice machine for video editing, and you could likely find one on eBay for a fraction of the cost of a brand new one.