Backpacker, it's gonna' change your life. There are a lot of books out there and the Orvis book is a good starting point. A 4 wt rod would be a good rod for smaller streams and would not be too much of a pain too learn to cast on versus a 3 wt. Don't know where you live but I would go into a flyfishing store and pick some brains and hold and cast a bunch of rods so you can find something that fits and is comfortable to you. There are a lot of choices out there and the price range is significant. Good part of buying from a fly shop is that you can get usually get some casting lessons thrown in for free with a rod purchase or for a nominal price if they do charge you. Most important is the knowledge that comes along with getting to know the guys at your local flyshop. Most people think fly shops are more expensive for gear and they are in some instances. However, they are capped on the prices that they charge for rods so if you do your homework on rods you will see that the rods they sell are on par price-wise with the same models at Sportsmans or Cabelas. You can also buy a rod you like cheaply on Ebay but do your homework and make certain that you can return the rod if it is nicked up or scratched, or has any flaws. I would maybe take a casting lesson and throw some lines on a bunch of different weight rods from different makers until you find something you like, then purchase. If this isn't an option drop me a PM and I can direct you to what I think are some good smooth casting rods to start with. Most really cheap rods cast like fence posts and can be frustrating for a newer flyfisherman.
As for waders, I prefer a breatheable stocking foot wader for fishing mountain streams and rivers where I will be moving around a lot and going from hole to hole. A lot more comfortable in my opinion and having guided in and worn just about everything I know they will last longer and make your feet much happier at the end of the day. Hodgeman makes an affordable, durable breathable wader but if you want to spend the money Patagonia and Sims make the most comfortable and in my opinion, most durable waders. Sims will outlast 70% of Patagonias but Patagonia's customer service is awesome should you have any problems. I fish in Patagonias and would put several serious Alaskan seasons and many many miles on them before I wore them out. I only wear boot foots when I am steelheading in cold cold weather during the winter and not moving around a lot. They are too bulky for stream fishing and tend to wear at the top of the boot foot if you hike around alot. Some people love them but it's a lot easier to strap your waders and a lightweight pair of wading boots on a pack than it is a heavy pair of bootfoots. Anyway, let me know if you have any more questions, I have been stricken with the flyfishing disease since I could walk and think it's great whenever someone else takes the jump.
-Cody