How much did BB charge you to format the laptop??? I really get annoyed when those people think they're doing you a favor by partitioning the hdd. Partitioning works when you have a very large hard drive.
Most laptops these days come with a 60-80gb hard drive on average. So, why partition it? The biggest hard drive I've seen for a laptop so far is 100-160Gb. Software code has gotten more and more complex so that demands huge lines of code. I'm not 100% sure about this but, I think Vista alone requires over 3Gb of space, and that's just the Operating System.
My advice to you would be to find the system restore cd that your computer came with the laptop. Pop it in, and when the windows install commences, reformat the hard drive to have one main partition (C Drive). That way, you won't have to worry about maintaining 2 separate drives.
As far as a removable drive is concerned, it is a good idea to have it if you're going to store lots of different media (pictures, movies, porn, etc.). Removable drives are nice to have because they are "hot swappable", meaning that they can be plugged in and out from almost any computer. What they basically are is an internal hard drive with an enclosure that has a usb or firewire port in the back of the enclosure so you can plug them into your pc. As far as those go, you can even get a 1Tb external hard drive but, that's going to cost you a pretty penny.
So bottom line, use the restore cd to reinstall windows and reformat the hard drive to have only one partition.
I hope everything works out for you.