For most trucks what's the best bang for the buck power-wise? So we're talking big motors...V8s  

You can get the Ford F-150 SuperCrew with a 4.6L SOHC V-8 or 5.4L V-8 ($895) for around $27,820.

you also have the Nissan Titan with a 5.6L DOHC V-8 for around $28,065/$28,475 that i personally like the most.

One of the best selling V-8s right now with two version with the 4.7L DOHC V-8 & 5.7L V-8 is from the Toyota Tundra CrewMax at $28,370. (its a little more for the 5.7L)

Horse power wise:
Tundra:  276 (381)
Titan:  317
F-150: 248 (300)

http://www.trucktrend.com/features/consumer/163_0806_2008_best_in_class_crew_cab_pickup/index.html  

You can also get the Dakota with the 4.7 V8, I think they bumped it up over 300HP now,  for about 24K.  

I've been eying the Nissan Titan with the 5.6-liter DOHC  V8 engine. I know its not a Chevy but the Nissan has been growing on me. It has 317 horsepower and 385 lb-ft torque.