First off I am a new member to the forum, though I have been reading posts on here for awhile. I am familiar with Apple products to an extent, as I have an iPhone 4S and iPad 2, both of which I LOVE! However, I have never had a Mac computer but I am seriously considering a new iMac. My PC is a Dell that's about 5 years old now and its not as quick as it used to be though it's still usable. But, after trying out the iMacs a few times at Best Buy and the Apple store, I really would like to get one, especially considering the amount of time I spend on my computer. The question is...which one would work best for me? I'm hoping that I can get some feedback on this. I'm currently in Grad school working on my thesis so I spend a lot of time writing and rewriting. I also have really old documents that were saved from microfilm that I view on the computer. I teach part time at a local 2 year college and those classes have an online component so I spend a fair amount of time online and reading and sending emails. Also create a lot of presentations and such. Games are fun but I'm not a hardcore gamer. I do like to do some video editing, but it would be more along the lines of iMovie stuff. I like stuff like google earth but I don't think I do anything that's overly taxing on the processor or memory. I do want to make sure that whatever I get will be able to keep up for awhile. At least as long as my Dell. I know this was kind of a long post but I wanted to give as much info as possible. I'm also aware that there may be a refresh in the near future but I've always been one to buy a product after the bugs have been worked out (the iPhone 4S being my exception). I'm pretty sure I don't need the top end 27". I'm more concerned with the difference between the 21.5" Base, 21.5 2.7ghz i5, and the 27" base. Is there a noticeable difference in processors and GPU? Also, do you think the 27" screen is worth the extra money? Again, my apologies for the length of this post.