21" or 27" iMac advice

[bokap]

Current computer is dual Mirror Door G4 that I am fine with except noisy and a dog on Canon DPP.
I want a new iMac, not sure if I want or need the 27 over the 21. Photography is my main use and use DPP and Photoshop now, plan on buying Aperture with new computer. Would the 21" duo work well for what I want. Would it be better to upgrade the ram to 8 gigs. Is the monitor so much better on the 27"? I don't care about watching movies on it. Would I get any benefit out of I5 or 17.
I tend to hold on to my computers for a long time.
Thanks
Bob

 

[techound1]

How big a deal is money? The refurb 21" is $1000; the i5 is $1700.

 

[JNickyJJ]

I think the 21.5 will be fine really

but if you have the money, you might find the 27 nicer

 

[MikeyJ57]

I think the 21.5 will be fine really

but if you have the money, you might find the 27 nicer

I considered both and decided the 27" was just too large. I opted for a refurb 21.5" and I love it! You'd never know it wasn't a brand new machine, and since I came from a 5 year old Dell laptop that was starting to drive me crazy, this new iMac is a dream! Fast, slick, and everything I hoped for.

 

[bokap]

Went to the Apple Store today and made up my mind. I decided since I keep my computers so long that I am going all out and I am buying 27" I7 with 8 gigs of ram Apple care and one to one, with Aperture.