I need to get a second monitor (video editing purposes) for my apple desktop (Mac Pro, 8-core, ATI Radeon HD 5870) however, due to budget constraints I have been looking at dell monitors instead of the standard 27'' apple monitor. Does anyone have any suggestions regarding PC monitors that work well for basic video editing needs (SD and HD projects, some color correction) on a mac?
Mine are a number of years old -- a 2405FPW and an 1905FP. Look at the different models and read the reviews to decide what you want. There is nothing different between a "PC monitor" and one sold/badged by Apple. There are a very small number of companies that actually make the LCD panels and everyone else OEMs from them. The differences besides the case the monitor LCD sits in are typically the connections to it and which specific LCD panel is inside (there are various different ones of different quality and cost). In short, any monitor will work fine on your Mac. The ATI 5870 on your Mac Pro probably only has display port connectors, so you'll either need a monitor with display port connections or just buy a display port to DVI adapter (typically around $30).
Now if planning to do color grading/correction or want/need accurate replication of what would be seen on a TV, you need a video monitor and output card (AJA Kona, Blackmagic, Matrox) in addition to the graphics display monitor. Remember that a TV and a computer graphics display are very different in how they handle the video signal. Discussions of this are probably better suited for the Final Cut forums here (or the forum for whichever editing package you are planning to use).
I have a 22" Dell widescreen monitor. I had been using it for some time but then one day flipped it to portrait mode. It makes so much more sense this way! Web pages and news documents (and e-mail) are all really long and don't fit that well on a widescreen.
Sorry to be a bit off topic here, but I have had good luck with Dell monitors in the past, but just wanted to encourage you to think about trying it in portrait mode if your monitor has the swivel capability.