iMac vs Mac Mini/Mac Mini Server?

Alright, so I am in great need of a mac of some sort (upgrading from a Toshiba L300 satellite notebook), however i do not necessarily wish to get a Macook. (too expensive!)

I have done some research and have with my budget (currently $1100 max) have narrowed down my options:

1) Mac Mini (2011) 2.7ghz dual core i7 processor with 4 gb DDR3 memory and one 500gb hard-drive. Intel HD Graphics 3000 processor with 288MB of DDR3 SDRAM shared with main memory. – $1019 brand new from Apple store.

2) Mac Mini Server (2011) 2.0ghz quad core i7 processor with 4gb DDR3 memory and 2 x 7200rpm hard drives. Intel HD graphics 3000. – $1099 brand new from Apple store ($949 refurbished from Apple)

3) iMac 21.5" (late 2009 model) 3.06ghz Intel core i3 processor. 4gb DDR3 memory, AMD Radeon HD 6750M graphics with 512MB memory
. – Approx $900 refurbished/second hand from eBay.

Which ever one I get, i plan on running Pro Tools (recording software) on it, which requires 4gb ram recommended, and quite a bit of processing power.
I also would do a bit of video editing, and a bit of gaming on it.
Which one should I choose? Any other recommendations?
Thanks

I have to say, I don know if any of the above will really make you happy.

First of all, you would need to get 8GB RAM minimum.
Second, you want a dedicated video card with dedicated memory, especially for gaming.
Third, wait a month or two and save up a little more money.

1. Good enough for most tasks. I have one with 8GB RAM that I am using as a media server. I would not use it for gaming or production work.
2. Great for file serving and the like, but the video memory in that one is shared with the system RAM. Not good for production work, worthless for gaming.
3. 2009. Old, slow processor. not much life left based on how fast software is upgrading and requirements are getting more stringent. ebay 2nd hand = no warranty.

Save more money. Look for the Quad-core i5 at least, and a AMD Radeon HD 6750M w/ 512mb VRAM. The lowest priced new iMac starts at $1200. you could probably get a referb from Apple for $1000.