There is some introductory reading available for new divers here:
http://www.newdiver.com/gear/divecomputers.shtml
http://en.wikipedia.org/wiki/Dive_computer

And here is a raving review of the Aeris AI dive computer:
http://www.northwestdiver.com/gear/20030729.php

well, I stumbled on your weblog while Googling for the solution to get the mt-moblog.pl script working properly on my server... anyway, noticed that you're checking out Suunto dive computers and hope my comment is not too late.

I've been using Suunto Stinger for a year now and I really recommend it. It's comfortable to wear and feel just like a normal watch (depending on the size of your hands) and it's really reliable.

The other model that's equivalent of Stinger but lesser costs is the Mosquito model - the same computing engine, but with rubber/non-steel casing and without Free Diving/Gauge mode.

The advantage of Mosquito over Stinger (I found that out after I bought Stinger) is that you can change the battery yourself without having to send to Suunto authorised shops.

Thanks for your comment Yusmar! I haven't bouhgt a dive computer yet, so your advice is most helpful. I'm trying to get my hands on a Suunto Gekko for my next dives to see if I like it - it's also quite low cost compared to the Stinger, but doesn't have a backlist screen nro computer interface.

Also have a look in Dive Rite (Nitek plus) before you buy.

I use it for about 2 years and i am really satisfied

I've been using a Suunto Vytec for 2 years and love it! I love the hoseless air integration - one less stiff hose to snag stuff on. I haven't used the gas switching - one of these days I'll start diving geezer gas! Great dive download software. Not too huge, but not too small - I can push the buttons in the mitts I need to wear in the cold fresh Canadian water I dive in.
The Gekko is a 'puter that I would definately try, is cost is the bigest concern. I'd trust any Suunto product, frankly. I had an Alladin Air-X previous to this - it was stolen - and I liked it, but the Suunto is far better in my opinion.

Suunto mosquito does have free diving mode. In fact its got every feature the stinger does, just not in the metal casing.

I've been looking for a computer myself, the mosquito seems to be definately the best choice, and all the reviews I've read have been very positive - it does everything I need for recreational diving and it also supports compression / nitrox diving if you want to go that far.

The quotes I've got in singapore flog the prices from the web too - around $280 USD cash price here...

I am just back from a few days diving in Koh Tao (Thailand). Several of the DMs there have mosquitos and have had problems with the battery contacts corroding. Hence they were of the opinion that the mosquito had good fucntionality but was unreliable.

I am also looking for a computer with almost identical needs as you.