The intel iMac I had in 2006 never really cut the mustard. The x1600 integrated graphics chip failed at games out of the box. With quite a few bugs, USB and firmware problems, many hardware developers were late getting drivers out. I swore off M-audio for good and went to MOTU. Lastly it started developing lines in the LCD screen in later years. I was lucky to sell it at all. iMacs had turned into cheap pieces of crap and I needed something new.
Lion is a great operating system and I need it regardless of cost because Windows is still endlessly annoying. I needed another Apple machine with Firewire. Enter the Mac Mini 2.5 ghz. I'm glad I got the more expensive one. This machine is dead quiet when doing menial tasks like internet surfing. An i5 processor is still quite good. The dedicated ATI Radeon chip is a must these days. I will never buy an integrated graphics (intel 3000 or 4000) ever again. The fan does seem to boot up quite loud while playing games or excessive hard drive use, but that is not a big deal. One thing I noticed is that it is actually cooler to the touch when playing games on high settings. This mac Mini with Radeon is able to play Dirt 2 with no frame drop outs at a medium resolution. It is sort of like PS3.5 graphics if I had to estimate. I'm happy with it because I know the intel3000 chip on the lower end mini and macbook pro is a total piece of crap and anything else worth buying is more like $1600, which is kind of an insane price point.
There are only two things I don't like about the Mac Mini. One is that firewire 800 needs a new cable to connect to my older FW-400 interface. It is not available in common office stores. Second there is no optical drive. I can't play DVDs or Rip Audio CDs. Thank god I had my music backed up. A low cost solution would be to get a 3rd party Blu-Ray drive, but even that may be a waste of money now.
Other machines I considered:
* A used 2009 Mac Pro - This computer only has slightly better performance at more cost than the mac mini 2.5. It would be easy to upgrade. The motherboard is still current. But you are lucky to find out for the 1000-14000 range. You can get a comparable machine for hundreds less.
* Macbook Pro 15" w/dedicated graphics - This one is too expensive and feels cheap. I tried the hardware in best buy and felt that the screen and overall hardware was crummy. No wonder Foxconn likes to riot. They are making cheap computers that get sold at ridiculous prices. The pro models don't have any of the latest chips and leaked specs for the new ones aren't much better.
*Macbook Air 13" - The 11" is really awkward. The design of 13" is actually more desirable than the macbook pros in person. This might work, but it has no dedicated graphics. Again the intel 3000 is something I need to avoid completely.
What to look for in a new computer if you are doing multimedia:
Quad Core chip or 2.2ghz or higher. Try to skip the Core2 Duos, they seem slower and run hot.
4GB of Ram Standard
At least 320GB HD or 120 SSD.
ATI or NVIDIA Dedicated Graphics (6000 series+ or GT+) Skip any computer with intel graphics 3000 or integrated graphics.
For most purposes a Mac Mini 2.5ghz is extremely powerful and will be enough for a few years. It is worth buying over a cheaper PC and the cheaper mini. What I needed was to run Lion. This box totally works for me.
Other Notes: Apple's magic track pad and mouse are total garbage! The track pad is barely adequate on MBP and standalone pad. Resolution-wise, It felt like it was skipping around. Pressing the entire thing down to click is ridiculous and just won't stand up to abuse in my opinion. The Magic Mouse felt like crap in my hands and cut into the inside of my fingers. It is a hard edged design and it is one of the worst designed mice I've ever tried. I'd rather use the 1998 USB hockey puck which not only doesn't hurt my fingers, it felt a lot more solid. Most of apple's hardware is garbage right now. Skip all the expensive peripherals and accessories and get 3rd party ones. Be wary of future releases and don't buy anything online without feeling it in person.
Another note: Apple's hardware lines have gotten completely confusing. Multiple lines and multiple configurations only benefit Apple's need to gouge you and not the consumer's needs. The power available in the lowest models is a complete rip off. The mid-range are not much better. Most people want to try the latest game at least once or twice and the higher end models do not represent what is currently available in the PC world.