The reason I didn't get the original Xbox was because it came into the generation so late and i didn't like the design of the casing (looked to heavy and bulky).
The X360 is a different story, as i like the design of the casing, but the reliability does completely put me off of buying the console. If it wasn't for the RRoD, i would definitely pick one up.
They have got 1 less sale because of me. I would say RRoD has affected sales a lot, as i'm sure there are many others out there who feel the same way as me.
If in future the internal layout is redesigned to fix the problem, i may consider getting one.