Giant Terrago 1997/8

I stumbled upon this site while attempting to find info about my Giant Terrago. I cannot find any trace of a similar spec bike or even colour to mine.
I bought it new in 1999 and it was the last of 1997/8 model that the shop owner was outing.
Its has aluminum frame/ magura HS 11 hydraulic brakes/ strx-rc shifters / deore LX rear derailler

This is currently my daily commuter.
The only changes I have made since new is to put a set of road slicks on. It's still running on it's original chainset, even the brake pads are originals !
This bike is light, the brakes are very strong and have not required any maintenance from day one and the gear change is still very slick.
I was thinking of either selling it to get a road bike, but I have no idea how much it would fetch, or upgade to 1 x 9 chainset to make it a more efficent commuter, as it on tarmac 100% of the time.
Any thoughts on either upgrading or selling ???
http://www.flickr.com/photos/99551664@N08/9382760285/
http://www.flickr.com/photos/99551664@N08/9385540314/
http://www.flickr.com/photos/99551664@N08/9385535888/
http://www.flickr.com/photos/99551664@N08/9385534518/
http://www.flickr.com/photos/99551664@N08/9382750005/