I believe the OP is in the same position as me in that when I looked for a first time dSLR having no prior experience I looked at both the 5D and 1D Mark IIn (opted for the 1D finally) when they were JUST coming out on the market (the 1D being ~6 months old the 5D brand spankin' new). The reasoning behind why I went with the 1D for a first time dSLR was for the simple fact that I figured if I learned a pro body, pro controls etc not only would I have a camera that'd last (and believe me the 1D series last) a LONG time but I'd "grow" into how it operates, the kind of IQ and features that maybe I don't need at the time but kind of nice to have down the road.
OP: It depends on your usage and what you'd like to do with the body since the 1Ds is designed for a level of performance that'd allow you to capture a lot of what you see around you quite easily due to its AF performance, battery life, ruggedness. It IS however heavy if you got a 580EXII and a 70-200 2.8 on it then it can weigh upwards of 9LB so think about where you'd want to take the camera and how long/much you're willing to lug around the body and lenses when going places. If you plan on shooting scene's with a lot of fast action, ski/sports/events, or you want the best performing camera AND are willing to learn/use/refine yourself then the 1D feels right at home. If all you care about is resolution, you don't mind if the body isn't weather sealed, (and lighter) focus more on portraits and don't mind having a video mode the can record in HD then the 5D Mark II fits the bill.