Good info. I've also been deciding what I want too. And why would I be upgrading already when I have the Audigy2 ZS Gamer and with a kick ass speaker system?
I went to my friend's house last night (came home around 3am by the way). She's got one of those brand new 10-speaker Bose system!!!!! OMG, that thing is REAL home theater. Not that I'm saying the Z-5500 is bad, but if you ever compare Bose to anything, Bose will generally come out on top. The bass, OMG, it's like an airplane coming in for a landing, it's like a train going through your house, it's like the sound of an earthquake right underneath you. I have never heard that kind of response from ANY home theater that I previously owned (Pioneer, Yamaha, and Sony, let alone computer speakers) do that kind of sound. I was watching Mortal Kombat and Mortal Kombat Annihaltion on it. Whoa...
That kind of sound has encouraged me to beef up my own computer sound system. I have been debating with going for the X-Fi Fatal1ty or X-Fi Elite Pro (more extreme, more power). Audigy2 ZS is just 'ok' when compared to the X-Fi spec for spec.
The X-Fi has a new feature called the X-RAM which will hopefully be utilized soon. New technology and good stuff. Video cards have been using onboard buffers for a long time, so it's no surprise that we're seeing more SDRAM on sound cards as our demand for more detailed audio increases. The idea is the same as that on graphics hardware - you gain better performance (lower latency) by swapping information between the onboard cache rather than going across the PCI bus. Also with the onboard RAM you can support much more in-game audio sources (more voices or effects like on a Battlefield 2 and UnrealTournament 2004 game as an example) or uncompressed audio (requires less processing) thanks to the buffer.
The completely redesigned Sound Processing Unit (SPU) is immensely powerful and produces the highest quality music and sound effects for any sound card to date. However there's a catch: not all software may be designed to take advantage of X-RAM. Much like RAM on a video card, developers need to specifically program support for X-RAM, so how useful X-RAM will be is entirely up to the game and software developers. As cool as X-RAM may appear to be, it will not benefit those who prefer using their hardware for music or media playback. X-RAM is purely for media developers and gamers at the moment. Not to bring a downer to this technology, but with any new technology, it always starts out this way. People doubt 64-bit CPUs, but here we are. The same will be true for X-RAM.
Now I've heard that the X-Fi XtremeMusic or the X-Fi Platinum version doesn't have X-RAM support. I'll see what I can find on that. Ok, never mind. The XtremeMusic and Platinum comes with only 2MB of X-RAM while the Fatal1ty and the Elite Pro comes wit 64 whopping MB of X-RAM. Drool.