Right now, I currently have windows xp pro w/ sp3 on my computer. I've been having a lot of problems with sound lately. Sometime when I would start the computer up, there would be no sound. Usually, I would have to go into the settings and click the options that were already selected. For some reason, I would start getting sound after that (without changing any settings). I think my sound card is dying and I'm going to get a replacement. I already know that I need a pci card. I use an old lcd monitor with built in speakers that provide me with clear sound. What type of card should I get? Should I go with 16 bit or 24 bit? How many channels should I consider (since I only have those 2 built in speakers)?

Something cheap, like this, should do fine.
http://www.newegg.com/Product/Prod [...] 6829180004

You only need 2channel for 2 speakers. Although more doesn't hurt. 24bit is better, although you won't hear a difference through those speakers.

Does it matter if there is an extra microphone and webcam w/ a microphone? Also, how good is encore in general? Are their cards decent? BTW, will the metal plate fit in a normal atx case?

It'll fit. And extra ports can't hurt you. Not sure about brand, but in that price range, it's all generic. The specs show good os compatibility and output at a low price. Feel free to look up others.