The R/T is a good choice (I also considered it), but don't minimize what you get in the SRT. It is more than just the 6.1 engine. It is the upgraded suspension, brakes, leather seats, HID headlights, hood striping, standard electronics, etc. If you try to add these things after you purchase an R/T, it will cost you much more than $7K.
Also, if you are looking at future appreciation, the SRT will have a much higher value because of the low numbers built each year.