its going to be the BMW v MERCEDES thing......i.e NIKON v CANON
One piece of advice I would give you is ...if its going to be a long term investment you need to look at LENSES.
All the big names will be going full frame sensor in the next year or so and not all lenses will work.
Have a look at
www.warehouseexpress.com
They are usually up to date when price drops are concerned, and they like jessops will even price match.
I have personally used the D80 and think its a cracking mid range/ beginners camera if you can afford it.
We use NIKON at work...but I have a CANON so I am not biased in anyway to a specific brand.
Best advice is to go to a decent camera shop and see if they will let you take one out for the day.
Its down to handling and how you like the individual controls.
Don't get caught up in the MEGAPIXEL battle.....10meg is plenty for most.