I love Dell - get it at home, get them for where I work.
My opinions:
Processor - Does not really matter - unless you have some "major" computing power needs - even the lowest processor Dell offers is good enough in most cases.
Memory - The most important - The more you can get, the beter. AT LEAST 512MB - 1GB if you can afford it. MEMORY MEMORY MEMORY - The more the beter.
Hard Drive - I think the least Dell offers is 40 Gig. And to get 80 gig is only a few $ more. Unless you plan on saving lots of data (music, movies, etc...) 80 gig will be more then plenty in most cases.
cd/dvd/burner - Depending on your needs - I would AT LEAST get a DVD player / CD writer. In the next year, you will start to see more and more applications come on DVD and not CD's to install.