If you want better, Creative sells a number of USB surround thingies, but IMO you would do well to skip straight to a Creative Recon3D USB. Personally, I find CMSS3D to be too sharp in the treble, and THX TruStudio Pro is the best sounding virtual surround processing I've heard, BUT all the DSPs have their fans (For me CMSS-3D is too sharp, and DH echos, THX in the Recon3D had a better sense of depth). NamelessPFG has offered to sell his Recon3D USB for ~$65, a good price. It comes with decent cords, so you can adjust volume from the physical device on your desk. I think the Recon3D USB could've been made smaller (some wasted PCB space, also designed to expand with a wireless transmitter for one of Creative's headphones), but it's still fairly small, about 1.5x the width of an iPod and almost an inch thick – your desktop amp will probably be bigger. Side bonus: easy enough to bring to a friend's house or hook up to a game console.
I ran the HE-400 alright off of the Recon3D USB, but somethings like soundstage depth definitely benefitted from double-amping. If you got an amp like the Schiit Magni, FiiO E09k, or a Little Dot i+, you'd still easily be in budget.
Personally, I'd like Creative to revisit the Recon3D USB: remove the wireless expansion, cut the size, integrate a better amp and switch to SBX if they think that's superior tech (haven't heard that DSP myself). Wasn't a problem for me: I just plugged in my tube hybrid amp and everything sounded great.
Edited by Evshrug - 5/18/13 at 5:35pm