$500 to spend on tools. What to get? Thoughts?

[scherp69]

Our local TV station recently had an online auction and I picked up $500 worth of gift certificates for a tool store that is known in BC and Alberta, KMS Tools. I paid $400 so get an automatic $100 savings on whatever I get. Before I bought these, I had noticed a 36 inch slip roll in their flyer for $549. That's what made me buy these. I went to the store today and one of the guys I know there offered me a 50 inch slip roll for $599. The have that one in stock and would have to bring the 36 in so they can give me a better deal on the one in stock. Only thing I'm wondering, although I've wanted one for a while, I don't know how much I would use it. Even though it would look damn cool in my shop. Here's a link to it: http://www.kmstools.com/magnum-50-slip-roller-3179

I'm just wondering if there are any other tools that would be better use of my gift cards instead. If you've seen my build thread, you'll know that I already have quite a few tools. Here's a quick list of what I already have:
- lots of hands tools, sockets, screwdrivers, wrenches, etc
- Miller MIG welder
- 36 inch sheet metal brake
- sheet metal shrinker and stretcher
- bead roller
- ring roller
- drill press, bench grinder
- air compressor with lots of air tools and wall mounted hose reel
- good shop vac
- good creeper and shop stools
- good cordless drill and impact as well as a good corded drill

What do you guys think I should buy? I don't mind spending a $100 or so more, but want to keep it pretty close to the $500.