Kind of unrelated, but a few years ago I purchased a Dell Ultrasharp 27" (image quality was fantastic, but monitor is ~$800+) however, the large size frequently gave me headaches because of the maximum viewing distance my desk could provide. Problems went away after I downsized to a 24" Ultrasharp. IMHO, 24" monitors are much well worth the cost.
Just voicing my unique experience, you could have a completely different experience with 27" monitors.