This is what I use also. There is a thread on here (I searched but couldn't find it again) That I followed that has you take out the dual 2.5" HD chassis and original HD, replace it with a 3.5 chassis for the Purple WD Drive and then get a SSD to install the OS on and about a 1.5' long esata cable and velcro it to the side of the inside case. This allows you to keep the DVD drive and everything looking nice.
If you're not in a hurry you can find some smoking deals in the dell outlet. You just need to check it often, they get snatched up quickly.