anybody have any advice about picking out a desk chair? the one I'm using makes my butt go numb if I don't have my feet propped up on something, and I'm starting to think that's not just a Quirky Bisexual Trait

@maya My advice would be:
1) Try them out *in person*, and if possible, try them out for a full day (though I realize that especially for cheaper options this is hard to do)
2) If you need to spend a lot of time behind a desk, get two different chairs that put you in different postures, and alternate between them. I've found that this helps a lot. You might want one of them to be a stool instead.
3) The best semi-affordable widely-available option that works for a lot of people that I'm aware of is the IKEA MARKUS. But try it first!
4) Second-hand 'commercial' office chairs can also be a good option. The Comforto 77 is a good option that works for a lot of people.
5) A separate backrest (ie. not continuously attached to the seat) often helps to keep a good posture.
6) No matter how good the chair, sitting for hours on end is always bad for your body. Take regular breaks - use something like Workrave to enforce it, if necessary. I've also found brief equipment-less core exercises to work very well for keeping my posture healthy.

IKEA used to have a *very* cheap and *very* good (if slightly uncomfortable) plasticky desk chair, the ALRIK, but unfortunately it's no longer available :( You might be able to find it second-hand, though!

@joepie91 thank you!! my friend advised that i probably had this chair tipped too far back so i'm going to see if its adjustment makes it more livable... but then i'll be taking this advice 100%.

@maya Ah yeah, if it's leaned back, then the 'raised edge' of the seat can be constricting blood flow in your legs, and lead to numbing - so that's definitely a real possibility. Chairs with extremely sink-in-y pillows tend to have the same problem!