Most of the tube-style bumps I have seen (and smashed) don't do as well as you may think. If you want really tough stuff, try ARB for a front bump. There are some really cool sites listed over in the Accessories forum, like Sonoran Steel (http://fastq.com/~sschaefer/store.html). Check those out too!
The big thing you want to look for is something that will absorb impacts without twisting your frame or breaking your lights. A well-designed custom peice from a local welding shop can work great too! I had one on my old '79 Bronco that took a double-wide trailer house off it's foundation and didn't hurt the truck! (odd story involving an impatient 7 year old boy and a big-block Bronco!)