Truck Forums - Newbie general questions

Total Newbie here... first post (well, actually second; the first is in the Truck Tech section).

I'm going to buy a truck. I don't exactly what kind yet; I'd like to ask for input/suggestions/recommendations/etc.

Just a couplerequirements...

1. Full size, V8. I do a lot of projects around the house, in the yard, car restoration, etc. I want a truck that, if I decide to buy a '69 Camaro, I can load it onto a flat bed trailer and tow it with the truck. AndI don't have to worry if the truck has enought "guts" to handle it.
2. Extended cab (not the full 4-door, but with the smaller opening door... at least one side).

Like to have, but not requirements...
3. 4 Wheel Drive
4. Full-size bed (can fit a 4x8 plywood sheet in the bed with the tailgate closed).

I'm not predisposed to Chevy, Ford, or Dodge. I'm thinking it will be somewhere around a 98 - 05 model year; I'd like to spend not more than $15,000.

So... the questions...

For each line (Chevy/Ford/Dodge), what's the first model year that's "ok"? In the range of model years that I mentioned, what's the best year? Anything special that I need to look for or ask about? Any particular body issues (like, are there certain years that are prone to rust)? I mentioned that I'd like to have 4WD, but is that a good idea (I live in Kansas where snow can be an issue occasionally)?

GM guys: Is there any mechanical difference between Chevy and GMC? Are there any significant cosmetic differences? I know GM had some trouble with the 700R4 transmission in the 80s and into the 90s... did this ever get straightened out? What year is the first that's ok? What year is the best?

Dodge guys:Is a Hemi worth it?

Ford guys: Is the 5.4L engine worth it?

To guys who have crossed over brands (well, really for everyone): Please give me your thoughts from a comparison basis (like, Fords are great, I'd never own a Chevy) (or vice versa).

And I didn't mention Toyota or Nissan... it seems they tend to be a little more expensive than the American trucks. Should I consider them as well?

I know this is a pretty big question; sorry for being a little vague. I've "casually" looked at trucks for years (obviously), but I'm just getting started looking seriously. So any and all input is great.

Thanks.