When i started diving i also considered what diving computer to buy. I like newest technology, however, after few discussions and considerations i bought cheap Cressi Newton for USD 275 (i bought it before Christmas and got 10% discount). My considerations were the following:
1) I am going to be involved in recreational diving only.
2) I will not need trimix, multiple gas switching
3) Air integration is good to have but this feature makes your dive computer more expensive
4) I will be diving during vacations only (it means 3-4 weeks a year)
5) Computer has to have Nitrox function as i intend to go for liveaboards.
6) I will be diving with wife (who is my buddy and has the same certification level). So, we will need 2 diving computers which double the costs.
7) I wanted diving computer to be big watch size
8) Diving computer should have ability to download data to PC.
9) I should be able to change battery myself in order not to be dependent on authirised dealers (in rder to avid situations when you are on vacation, need to change battery and nobody is able to help me as there is no AD in that country).
10) GPS, color screen and all other gimmicks are ok, however, they definitely not worth to pay additional money.
As a summery: if you are recreational diver you need only simplest diving computer, if you are involved in technical diving then there is another story.