Which would be better for FCP and Pro Tools? Mac Mini 2.3GHz i7Quad or iMac 2.9GHz i5 Quad?

I apologize in advance if this is a dumb question. I've been a post production recording engineer and sound editor for 20 years, but for the last 4 I've been on disability because of arthritis and Crohn's Disease and so I haven't been keeping up on the technology. I'd like to start trying to at least do a bit of freelance work but my MacBook Pro 2.2GHz Core 2 Duo just doesn't have the muscle any more.

Keeping in mind that cost is absolutely a consideration, I'm looking at a Mac Mini 2.3GHz i7 Quad Core 4GB RAM (or 2.5GHz i5 Dual Core 8GB RAM) and a 24" Dell IPS HD monitor or an iMac 2.7GHz i5 Quad Core 8GB RAM 21.5". I know both monitors would be the same resolution and the iMac monitor would probably look better, but I don't know which computer is better suited to my current needs. At least for now I'd be running Pro Tools 8 and FCP Studio. I know I'll have to learn FCPX at some point...but one thing at a time. I don't need to have both programs open at the same time, so multi-tasking isn't a big consideration. For the most part, data would be on external USB 3 drives. But a couple of other questions. Would I need to add RAM to the Mini? Will the Mini support an IPS monitor and ALSO an HDMI monitor as a preview screen? How much difference is Dual Core vs. Quad Core? I could get the 2.5GHz Dual Core Mini for only $600, and then add the extra RAM.

I'm one of those rabid Apple lovers so I'd obviously prefer the iMac, but I can't spend an extra couple of hundred dollars just because it'll look better on my desk. However LONGEVITY is as big a concern as cost. I'm likely going to need this computer to do the job for quite a while! So I know that for now the software I'm using doesn't really make use of multiple cores, but newer software will right? Other than security, is there a big difference between the i5 and i7? Also, I don't need to start tomorrow, so what is the rumour mill saying about new release dates? Will new iMacs have Retina displays? I've checked a bunch of rumour sites but nobody has any RELIABLE information.

I'm sorry, I know it's a very loooong question and it seems like I've done no research on my own. I have done some, but the answers vary greatly. So any advice would be GREATLY appreciated. If I can spend $900 dollars instead of $1300 I can eat next month (that's a joke - it's not THAT bad). But I don't want to regret the purchase a year from now!

Actually, the most important hardware component in video rendering is videocard (GPU).

iMac has discrete NVIDIA GeForce GT 650M adapter with dedicated memory, while Mac Mini has integrated Intel HD Graphics 4000 card. The difference is jaw-dropping. Some benchmarks to prove this:

• 3DMark 11: 2320 points in 650M, only 604 points in HD 4000.
• 3DMark 11 (GPU): 2112 points in 650M, only 524 points in HD 4000.
• 3DMark 06: 13453 points in 650M, only 4410 points in HD 4000.

I believe, you got the point. HD 4000 is a bit less powerful than NVIDIA 610M. Quad-core processor will not matter when integrated graphics will render every frame for 2 seconds.

Geekbench is more about CPU, than GPU. Video editing is more about GPU, than CPU.

8 Gb of RAM is enough for working with 4K@24fps projects.

This fall new Macs will be released with better hardware and the new OS X Mavericks will roll out with performance (CPU and memory) improvements (more free RAM for FCPX).

So I advice you to wait for a while with buying new Mac. Get better.

According to everymac.com the mac mini configuration is more capable (geekbench results for 32 and 64-bit OS'es respectively)

Mac Mini 2.3GHz i7 10626/11825*

iMac "Core i5" 2.9 21.5-Inch 9202/10756*

personally i would add 4GB or 8GB more to the mac mini at some later time. (not at the time of buying though as apple tends to charge more than say, OWC)

I think both computers would serve you well for what you want but i would prefer the Mac mini as the iMac is a bit less capable power wise and additionally more difficult to upgrade..