My thoughts:
1. Coupe price seems reasonable. I'd check it over thoroughly and since your a 1st time'er have a qualified viper tech check it out for you, along with perhaps an owner or two, before ever entertaining purchasing it. (goes without saying not to use the viper tech at THAT dealership).
2. Who knows what the trade in value is on the 06's or when the 08's will be available in mass quanity for a lot of 06's to be traded in. I for one am keeping my 06 until something RADICAL comes out from Dodge, maybe an ACR or the 09/10 if its a complete redesign.
3. I had a 2002 graphite and silver stripe Viper, not FE (but there is no difference, only coloring). If I had to do it again, I would have still bought the 2002 at the end of 2002 even though 2003 would be available shortly. It was a great adventure, lots of fun, and I can say I owned a gen 2, and understand some of the "raw viseralness" that is a viper. That being said, I own a 2006 coupe. In the beginning when I first bought the coupe, I told people (even after purchase), if I could have gotten a BRAND NEW 2002 ACR under warranty just like my 2006, I would have taken the 2002 ACR instead. Thats because after putting 60k miles on my 2002 ACR, I really loved it, and got attached. Then after putting almost 13k miles on my 2006 Coupe, I can say that is no longer the case. The new vipers are just better. Thats it. I can explain why, but I have done that before in another post. Now once again if I had to do it all over again, I would get a 2002 ACR because it was fun, but in 2006 if I could have had an ACR or a srt-10 Coupe, I now know the srt-10 Coupe was the right choice.
Go with the newest Viper you can afford, often times its got fixes and things learned from previous generations already incorporated in it.
Jon