Dying imac. custom build pc, Hackintosh or mac mini? Help!

I need a new computer asap to carry on working on a few projects as my iMac is dying (graphics issue that most 2008 models get after a while - another long story).

I am going mental trying to decide as i dont have much time…

Initially i thought it will be best getting a computer with OSX on it (either mac or hackintosh) and use time machine to migrate all my apps and settings as before. However my current system is OS X 10.6. A new mac would run mountain lion 10.8. Would i be able to run Nuendo 5 with my plugins, FCP and a few other stuff if i use time machine to migrate on a 10.8 system? I guess i would have to get a few updates for my apps to work correctly on lion, right? or is this a tricky route?

A second solution would be to build a hackintosh. Either one to be compatible with with 10.6 or for 10.8 mountain lion. I need to carefully pick the components depending on what OSX version i want to run on it. So if i cant migrate my current system on 10.8 platform i need to build a 10.6 hackintosh since my current imac runs 10.6. I havent done it before but i have experience with building pcs in the past. However I hear sooner or later i ll have minor issues here and there (with software updates) and i would have to fiddle with it all the time. And i dont really like that.

Another option is to go for the new mac mini with i7 2.3Ghz processor (i7-3615QM). It has a single 5400rpm drive which i can later upgrade with a fusion drive that combines a SSD with a SATA one.

A final option is to build a pc with windows 7 on it. But that means i ll have to reinstall everything again and some programs might not work on windows (fcp for instance).

It will my be main DAW. I work with nuendo 5 for post production (sound design and mixing) on relatively small projects. I dont use a lot of plugins or softsynts. I also do a bit of video editing from time to time with FCP.
My current imac is from 2008 and runs on intel core 2 duo 3.06Ghz processor with a 512MB nvidia card and 4gB of RAM. I never use more than 70% of my cpu in nuendo. I can do my job fine on this machine.
The i7 on the mac mini is a lot more faster than what i have now. I can even hook up three monitors using the HDMI, thunderbolt ports and an usb to dvi adapter… But overall would the mac mini be ok?

I am a bit worried about the graphics as i doesnt have a dedicated graphics card. I need accurate video playback when i work but that doesnt involve anything more than smooth playback a single video file (a few times in HD rsolution). The intel 4000 chipset should be able to do that, no?

Money wise i figure i need about 800euros for the quad core i7 2.3 Ghz mac mini and around the same amount for a quiet pc with similar processor and acoustically insulated case, quiet PSU etc… Obviously i cant afford nor i want an overpriced mac pro…

Sorry for the long post. I hope someone in a calmer state of mind can advise me.