All I can say about that is that I was really disappointed with the line in 2 also, that was my reason for buying the platnum version (before I found this site), fortunately, I just recently started using sound fonts for drums and have one use for the live drive other than headphones, the midi port. I have more spliters and adapters going into the rear line in than you can imagine, (I'm to poor to buy a mixer).
It's been a year and I'm just now running into the limitations of SBlive, if you can afford a mixer (sorry can't help you out there, I haven't researched the cheap ones yet), I'd suggest after making some mistakes in the parts I bought, to ask some people about mixers in your price range before you upgrade to a pro sound card. you should be able to get some life out of the SB while you learn all the many softwares and software features you need to, besides, if you can learn to control the SB you can master a high end card (OPINION NOT FACT) when your ready.
my upgrade shopping list in order:
0) fret job for my guitar (comes before recording)
1) Cheapest recomended mixer and quality cables
2) software, from Cakewalk Guitar Studio 2 to Sonar
3) High end audio sound card compatable w/ SBlive
4) Amp worthy of miking (I'm strictly direct line at the moment (year(S))
5) Quality mikes
6) dedicated system for DAW or laptop for other purposes
7) Bass guitar (it's been years but I got pretty good) essential before I "release" any songs and midi won't do
8) full size keyboard controller w/ weighted keys
9) the list just keeps going like this for pages instruments, sound proofing, more mikes, more software, by then another system rebuild carsHOUSEBOATWIFEANDKIDS
MOREAMPSMORESOFTWAREAHHHHHHHHHHHHH
my finished upgrades :
1) overall system upgrade P3 800, 256k ram, Asus cusl2 mobo, additional 40 gig hard drive for file storage
from AMD K6 3 450, 128 ram(replaced,not added to)
2) replacement pickup installed last week and (backordered and waiting) replacement
floyd rose pro tremlo