Road Cycling - Advice needed on my Trek

Here's my situation. I have a Trek 790 (cro-moly frame & forks) that I bought used about 7 years ago. It has a Shimano triple chainring (SG) and a 7 speed cassette. Derailleur and cranks say Shimano 500 CX. Deore LX hubs Titan Tour rims with slicks. MB-style handlebar with gripshifts and bar-ends.

The bike had about 750 miles on it when I bought it. I put 2-300 miles on it when I first bought it, then got lazy and stopped riding until recently. Now I'm starting to ride more regularly again with a budy (provides great accountability for me). He rides a Trek 1200 and probably logs 100-150 miles/week. I'm working towards that but am currently in the 35-40 mile/week range. My interest in riding is mainly fitness, but I'm not opposed to going fast either :D . It's interesting to me that the frame geometry between my 790 and his 1200 seems remarkably similar.

Anways, to my questions: First off, what quality level of components do I have here?
While washing my bike tonight I noticed that on both the chainring and cassette not all the valleys between teeth are shaped the same - is this by design and why? Also, not all the teeth are the same height, I'm assuming this is due to wear?

The teeth wear has me wondering what to do. I'm not ready to run out and replace anything until necessary, but I'm at least starting to think about it. I'm assuming I'll be able to simply swap out the chainring and/or cassette when necessary? Will I want to move to an 8 or 9 speed cassette at that time and what extra would that entail?

Lastly, I'm wondering if this is a bike I'm going to be happy putting a lot of miles on or will I be happier with something more geared specifically for the road?

Unless the bike is a mud puppy I doubt chainring wear is enough at a 1000
to 1500 miles to be noticeable. Chainrings are usually good for 8k to 15K miles.
What you may be seeing is one of the major innovations of the '80s: that shaping the teeth and adding cuttouts on the larger chainrings with small rivets greatly facilitates chain pickup and hence shifting. Next time you are at a
bike shop look at new bike chainrings and you will see this in the pristine mode.
Regarding the other question, your bike should be left as is and you should really look at a new bike. Prices and quality levels of components have dramatically improved in the past 6-7yrs such that a bike that fetched $2k in '96 is now sold for $1300-1500 for a similarly equipped bike. A bike in the $800-1k range would be a significant upgrade from your present bike, and if your estimate of future interest warrants a $1500 bike will satisfy for years to come. Just be careful about the current rage for builtin headsets. www.canecreek.com (if error search for Cane Creek website) has an essay about these. Steve

I would agree with sch, don't put money into the bike. If you are going to ride that many miles I would get a better road bike. You could always look into a used bike until you get the miles up, then spring for the shiney new one. Who knows, with a real road bike you might be able to put in miles than you think.
Good luck
Dave