Unfortunately the answer is "It depends"

I being a loyal dell user since many years wouldnt hesitate to say go for dell but to be honest i've used compaq for a year and it does a preety good job. Here are few thing that you would like to consider.

1. Dell has exceptional costumer service if you buy enhanced costumer support or what have you.. then you would  never waste time trying to resolve the problem by yourself.

2. Years back dell was not assembled as properly as compaq (remember the sony battery recall by dell) was but but in recents years dell has grown a lot and now with systems like Vostro and Insprion you are going to get the best out of the machine you won, for instance take it like this you are comparing ford with nissan...(but dont get into this example solely its just to give you some sense of what i'm trying to say)

3.For affordibility i would go for dell, but if you want relialibility go for compaq.

Final advice if you are considering compaq then check out TOSHIBA. If you are willing to spend atleast 1k and up then you get a very good system. Once again someone might be able to give you more rigid answer and take their advice into your consideration.

Good Luck

YekloYatri