I don't care much about bass in headphones, but in speakers I'm want a lot of bass (so I can feel it in my chest and whatnot). What's a good pair of desktop monitor speakers that have serious bass? Under 500 dollars I think...
Look for something with 8" woofers. However, even the best studio monitors are not going to give you much below 45 Hz, and most of them have a subsonic filter that cuts out everything sub-35 Hz. That's provided you have a very well acoustically treated room...otherwise, this is likely to be even worse with lots of peaks and nulls in the low end frequency response.
I have the Prodipe Pro Ribbon 8's (see here) and they do thump fairly well, though it's highly dependent on what your room looks like as well as where exactly in the room they are sitting.
If you find you have low-end response problems you can always buy some mineral wool and engineer your own bass traps (which I am intending to do myself), provided you're willing to DIY a bit, see this.
I would suggest these.
When you say you want 'a lot of bass' what kind of bass do you mean?
Depth. That long, booming drone that stirs the bowels as it extends down below 40Hz. Where ordinary music rarely treads?
Weight. Where the drums crack and bass notes almost snarl at you. A high SPL above 40Hz.
For the former you want an 8" or ideally larger driver and/or a specialised sub.
For the latter the order of the day is a powerful amplifier and twin mid/woofers 5" or greater.