Ya know what I like for a pre-w/o boost? Skittles. Just a little bag like the ones that you get for Halloween. Either that, or something similar. Just gives that little extra sparkle to the day...and a little extra sugar for the fire that I'm about to light in the weightroom.
As mentioned, BCAAs. Do it. No questions asked. If you're not training with them, then ... Why aren't you using them again??? Seriously - do it.
Just because you threw the word "pump" out there, I'm going to throw in a recommendation for something that's often overlooked, very effective, very very economical, and will actually mix in really really well with your chosen BCAAs (which you are now going to go out and buy because you feel like a bit of a fool for not having done so already, right?)

Controlled Labs Glycergrow. Mix a few scoops in your pre-w/o drink, chug it down, and enjoy. The "pump" from it is quite nice. Comparing it on a price/serving level, it's WAY better than other dedicated pump products out there. Last time I had it, I did a WHOPPING 6 scoops per serving - WAY more than recommended, but I am a bit of a big tool - and using it on w/o days as suggested, one tub lasted me about 3 months. Simply can not beat that for economy!
I say give 'em a try. Go with a BCAA and Glycergrow. Spend a few bucks more for a quality BCAA like Xtend or AXcell (which you can get for HALF OFF on the AX site right now, WITH a free shaker), and spend a few bucks less on a quality pump product by going with GG.
/my 3 cents.
