Sounds like you got a lemon of a Tacoma. I have a 99 Prerunner with 145K miles that has been mostly trouble-free. The problems I had with mine were rear axle oil seals, a cracked exhaust manifold and a dead battery. The rear axle oil seals were a breeze to replace, and the cracked exhaust manifold (which I admit is quite common with the 2.7L) gave me an excuse to replace it with a header.
I haven't necessarily abused my truck, but I haven't babied it either, with the exception of giving it regular maintenance and fluid changes. I off-road it on occasion, which can be a little rough for a 2wd, but I never subjected it to anything really rough. Even so, I'm amazed at how much it has put up with without breaking down on me.
Sounds like you may have gotten hosed on the rear axle seal and rear bearings. Both rear axle oil seals on mine went out, which is common on most Toyota 4x4s, including the older ones (They went out on my 92 4Runner, too). They're only like $7 a piece. Replacing them is super easy.
Why did you have to get the wheel bearings replaced? Have you seen the size of the rear wheel bearings? They're huge and super strong and rarely ever break. The few that I've heard of breaking are from those who've really subjected to their trucks to some really hardcore off-roading on the rocks - Robert, of Frankentaco fame and Tim Jones both come to mind - and those two guys really abuse their Tacomas while doing hardcore rockcrawling, including having done the Rubicon and other super tough trails. I had mine replaced not because they needed to be replaced, but because I stupidly thought it was a good idea when I replaced my rear axle oil seals. One of the master mechanics with more than 20 years experience told me he's never had to replace the rear wheel bearings on any Toyota truck given how big and strong they are. But maybe you got a rare lemon?
I've heard of the rear main seal going on a few 2.7L engines, but mostly on manual tranny equipped trucks. Is yours a manual? I've never heard of the front crank seal or u-joints going, though. Toyota u-joints are supposedly tough, from the posts I've read, and although I have come across a few posts here and there from a few that needed replacement, they are far and few between.
The rack and pinion is one of the weak links when it comes to replacement part on the Tacoma, unfortunately, especially if you off-road and abuse your truck alot, at least from the posts I've read at tacomaterritory.com . Same goes for the tie rod ends, although most of the ones I've heard that need replacing are the inner ones, not outer ones.
As for the windshield leaking, I don't remember ever reading a post about that. Maybe what Mechanic58 said is true about driving over alot of washboard roads at high speed? Either that, or you really did end up with a rare Toyota lemon.
Well, sorry to hear about the numerous problems you've had with your Tacoma. Hopefully the problems were fixed.
