When deciding which type of computer to buy, consider how you will be working and which option would be best for you. If you are going to be working away from the office from time to time, you might choose a laptop. Make sure when you are using if for extended periods at your desk that it is on a stand with the screen at eye level and use a proper keyboard and mouse.
Consider a large external hard drive for making mirror back-ups and storing large files and make sure you also have an online back system such as Carbonite.
For lots of advice and free tips, check out the FREEBIES page at the VA Success Group