Now admittedly, I'm a bit bitter about a problem that's not really Creative's fault. I bought an Audigy 2 ZS for my laptop using PC Card...and then the next wave of laptops only came with an Expresscard slot. So, I ponied up again for an X-Fi card that fit the Expresscard slot...and then laptops stopped coming with those. Now I fully admit that Creative isn't to blame for that, but it is sad just the same. However, I digress.
I use my onboard audio for nearly all of my listening needs. My internal speakers are utter crap (I think one is blown, actually), and thus, even if Creative added all the super-duper offboard processing in the world, it wouldn't sound any better than what those speakers can pump. Adding a nice set of Sennheiser or Denon headphones, I can start to hear some of the MP3 sizzle in the 128kbps MP3s, and a handful of 192's, depending on the song and the encoder and settings used. Even playing video games, the difference between 'Good Enough' and 'X-Fi Good' never comes into play, because it's the nuts-and-bolts of the big picture that will make or break it in either direction - if the sound effects and musical score is good, the miniscule difference an audio chipset will make has nothing to do with it. If they're crap, a ZxR processor isn't going to change anything.
That being said, I still use offboard audio hardware on a regular basis. I use my Rane SL3 to DJ with Serato. Even if it wasn't a de facto hardware dongle to unlock the Serato software, there's no motherboard chipset that supports 2ms latency from end-to-end of the audio path. In other words, my SL3 can reliably take an audio signal from my turntable, translate it into speed and directional data, and send MP3 audio back out, in 2ms. Creative doesn't make hardware like that. The story is pretty similar for my Audio6 (which I use for Traktor) and my Connectiv (which I used to use for Torq and Deckadance, though it required closer to 5ms latency to be stable). I have a MobilePre USB that I use occasionally for XLR and 1/4" recording. These are niche products for niche purposes, but the fact that your local Guitar Center sells a range of these kinds of interfaces demonstrates that there's indeed a market for discrete audio hardware. Creative just doesn't make it.