your mobo will have an onboard nic yes... a 10/100/1G nic, so no worries there. well, if nothing else, you don't need to have an X-Fi for sound... I have an Audigy2 ZS that sound awesome to me...
Newegg doesn't have it, but I have the card only... you can try this one... I have heard decent things about it... Audigy 4
If you need to save a few more pennies, you don't NEED to have a second optical drive... a good burner will work for now... you can always upgrade later if you wish..