What are other people building or buying?
That is what I need some advice on... I have been out of hiking commission for almost a year (long story) and because of recovering from some ankle surgery, need to find a way to get some non-impact aerobic workouts. I haven't been on a bike in over 5 years, and haven't done any real mountain biking. So, we are talking about someone who is 50 lbs overweight, out of shape (the only time I was in worse shape than I am right now is when I had pneumonia and couldn't walk across the room without getting winded). I know I have to start out slow and easy. But what to buy? I can't afford a really expensive bike, and with the riding I plan on doing, it would probably be a waste of technology. But I want something that will do me in the future as I get into better shape and want to tackle some tougher terrain. Any advice? Your talking to a real novice here and I don't know where or how to get started. 
K9,
I'll second the recommendation of Coates - they are the only store I really have been pleased with.
You really need to figure out a budget for this. If you want a pretty decent bike but have a low budget, used is the way to go. You can get *very* nice bikes used for $100-$500. You can also get serviceable new bikes in the $300 range. It depends on your needs and commitment. Brian is absolutely right about the grades here. The flattest extended ride in the WW area is the rolling paved road at Table Top Mnt, and the longest section of flattish streets in town are some of the East-West streets, and most of them are not flat.
That means you need a triple with a chainring in front that's at most 26 teeth, and preferable a cassette in back with a bailout cog of 32-34 teeth. Even if you really ride this bike and get stronger, your first times going up streets like Sheep Creek may require a very low gear. Heck, I'm a pretty strong rider and sometimes I'm plain tired out and want something very low.
Brian recommends a hybrid, and my only concern with hybrids are they tend to come with useless seats and are designed with the disadvantages of a road bike and a mountain bike, and few of the advantages. On the other hand, the market is offering better and better alternatives finally after a decade and more of poor options.
If you are in your 50s and out of shape, then you should find a bike with a comfortable position and wide range gearing. Most inexpensive new bikes that accomodate these needs have two main drawbacks - they come with flat mountain bike bars and they have Gel/squishy saddles, with seem to a newbie like a good idea but they give absolutely no support for the important parts of your behind. A harder but wide and contoured saddle is far better. The flat bars offer you only one hand position, which can be very hard on your wrists.
REI has some interesting bikes that you might want to look at, even when they exceed your price range. They can serve as a model, and there is an REI in Rancho. The Safari, the Transfer, the Randonee, the Buzz, and a few others are worth a look. I like the Randonee and Safari because they are equipped to be comfortable for long rides, and come with handlebars with multiple positions.
You will here all sorts of conflicting advice and hype at different shops, and even in the same shop by different people. It's a frustrating but inescapable part of buying a new bike. I do think Coates is better, usually, and there are some people at REI who know what they are doing. Just go in knowing some of the fundamental things you need, and don't stray from them. In WW, very few people ride and I suppose it is mainly a matter of the road grades. I see most people out on mountain bikes with wide knobby tires that do not leave the asphalt, and I think that maybe more would ride if they had parts that better suited their intended purposes.
good luck.
