Actually 4 doors are 2001-2004 (and mine was made in Early 2000

)
Also frame recall ended for...1999 or 2000 models?
I don't know how much better fuel economy the 05-07 tacos are, but the interiors are a lot nicer, and more versatile (storage) and they have more power. Not to mention there are more available in standard (if thats your kinda thing).
My 3.4l gets 15.8l/100km (14.5-15mpg)consistently, with 31"nittos and a canopy usually loaded with tools(30%highway/70%city miles) best tank of fuel i got 450km but consistently get 350km/tank.
I know a guy who has a 2007 tacoma extra cab 4x4 auto and gets about 17-18mpg mostly city mileage.
I did the math and i got the 2001 Tacoma cause i thought i could only afford 10000 but if id spent 14-17000 on an 05+ i could've saved almost 900 a year on fuel (fuel is REALLY expensive in Canada)
The pre-04 Tacoma is really reliable, i've heard of some problems, but nothing too major, some people have a problem with the cab leaking, but dont get a sunroof and you should be fine. My 01 was given rebuilt status 8 years ago, and its hella fxxxing reliable.
05 was a weird year for the new tacomas so if you want newer go 06+. I also noticed pre-04 has an overall less tall cab, but has about 1 inch more clearance and seats lower to the floor, like a 4runner.
Anyways mine was a rebuilt 01 tacoma double cab trd fully loaded wit Rear Locker- 8500 non rebuilt
if you search a while you should be able to snag an 06 Double cab tacoma Trd Sr5 5ft box for 16-17000 with about 100k somewhere, that's what i would do, more power, more luxury, tougher bed, more aftermarket options, bumpers, sliders etc.
Anyway have fun, do some research peruse craigslist and autotrader, everyday.