Im a big fan of the Sport Editions, but i wouldnt "put down" any other model. Like others have already stated, "It all comes down to your specific tastes". I really like the hood scoop, the V8 and the tube steps & rack, so I got a 2008 Sport Edition. My first purchase of a 4runner was of my 2003 Sport Edition V8, with the textured gray plastic cladding, the OEM push bar in the front (yes, i know its just plastic, but i like the look!) and i still own it to this day.
Others who want some more luxury, want the NAV or the leather go for the Limited. Some who dont need any of the above and go with the SR5, it'll do the same job without the fluff. Again, it all comes down to your personal preference.
Others will wanna :AK47: me, but i would just add that i hope that if youre buying from a dealer that you'll haggle a bit and get an extended warrantee. I didnt get one on my 2003 only because i bought it from an Acura dealership in NH. The truck was NEVER "problematic", but there were some typical items that needed replacement: The front calipers 2 times, the blower motor's resistor, the CV boots, and thats all covered on the warrantee. I paid $1000 for the one i bought for my 2008, and it's already paid for itself when it needed new front calipers, costing $1100. Again, i didnt pay a dime, got a free rental, etc.
Good luck, and remember to take pics and post them in here when you pick it up!