Need Help Choosing 2011 refurb iMac 2.5 i5 or 2.8 i7?

[HF7035]

I am fairly new to Apple other than my iPad. My 5 year old Dell PC is dying so I'm ready to make the switch to a 21.5 iMac (27 in doesn't fit in my office).
Other than the normal word processing, photo editing, browsing stuff, I want to convert VHS tapes to digital and burn them to a DVD. I also want to edit some HD digital videos and burn them to DVD as well. I also occasionally make photo montage videos (ala photostory 3 if you're familiar with MSFT products). I don't really play games - spend enough time on computers as it is. I will probably want to run windows at some point as I am sure I have some programs that are old but I will want to run for whatever reason.

I tend to be a little impatient in terms of boot up, processing, etc. I am pretty comfortable with computers so figure I'll upgrade the memory on whatever I buy. I was looking at the base 2011 21.5 2.5ghz i5 for $979 (refurb). I just missed a 2011 2.8 i7 BTO on the refurb site for $1229. Is the base model sufficient or should I hold out for the i7 BTO -- or do you all have a better suggestion? I am assuming that the 2.7 i5 for $1189 is not worth it other than I get a 1TB HD and a better graphics card. I would like this to be useful for at least 4 years.

I suppose I would consider a base 2012 iMac if you all think it's worth it although I'm a little put off by the 5400rpm HD and the fact I cannot add RAM myself. I realize this is a tough call since there are no benchmarks yet.

Thanks for your help.

[scruby]

I would always go for the higher end processor certainly if you want your mac to stay for a a couple of years. Btw since you want to do alot of burning.. the 2012 imac has no burner so you have to get an extra usb burner with that