Well, I can't answer you regarding the difference between on-board sound vs. Soundblaster, but you always want hardware acceleration, whether it's for sound or video. Software acceleration is found in cheaper boards because it uses your CPU to process the sound. The manufacturer saves on the cost of an on-board processor. This makes your machine slow down a bit because processing sound is very intensive.
Hardware acceleration utilizes a processor on the sound card to produce the sound, thereby freeing up your processor for more important things. Not being a real audiophile, I use my on-board sound (C-Media). It's more than adequate for what I'm doing and for listening to music. Most low end computer speakers aren't very good, so you'll get more of a boost if you buy really good speakers. They start at around $100.00 US and can go to $500.00.
I bought a pair of Bose Media Mate speakers for $99.00, which did wonders for my sound. There are of course better speakers, but these little beauties are good for desktop use where you don't have alot of space. They have amazing bass for such a small unit. My wife even likes them, and she hates computers.
Sorry to get so long winded, but thought you would like the info. Buy the best speakers you can afford and go with hardware acceleration. Soundblaster is a good name in audio, so you really can't go wrong with it. If your Asus board is fairly new, I'd look up the specs and compare the sound chip's specs with the SB board. Chances they're fairly close.
i'd have to say the nforce2 audio is better than the live!'s. it's 4 years newer (an eternity when it comes to computer parts) and has hardware accelration. i upgraded to an audigy from my old live! and notice better sound quality, not to mention features. and i recently got to play with an Abit NF7 (nforce2) and i'd wager that it has even better SQ than my audigy.
i just looked up the A7N8X and it has nvidia's soundstorm audio... which is certainly better than your live!. soundstorm rivals the audigy2 and other new high-end cards. definitely try it out.
 okay, asus' site is misleading. the base A7N8X doesn't have the soundstorm audio. only the deluxe model does. but i think it should still be better than your live!.
Wow thanks for the informative and intriguing responses
first I would like to point out, and its on the site here, that the deluxe doesnt have soundstorm certification. the audio difference betwween regular and deluxe is 4.1 and 5.1 respectively.
Second when I go to run the Dxdiag utility it says my sound is not hardware accelerated supported.
I get weird distortion feedback noises in the speaker. Then again it could be 4 years of playing Slayer very loudly through the 2.1 logitech speaker set.
maybe next year I'll get a better soundcard. speakers first I guess
first off, the A7N8X Deluxe most certainly does have soundstorm cert.
Also, I went from an Audigy to the Soundstorm, and Soundstorm is just as good!!! I was using Paradigm Mini Monitors (home theatre speakers) with it, and the sound quality of the nForce is just as good as the Audigy. also, it uses less CPU than the Audigy, stick with teh Deluxe onboard....