isn't the Q10 a 20bit A/D converter? there are much better converters available now.
as far as convenience from not having a power cord and being able to plug everything in from the front of the computer, there are other units which will do that.
M-audio Delta 1010 has a PCI card with a rack mount breakout box. all connections are on the breakout box.
any of the USB and Firewire devices are all accessible from the box. some units require a separate power supply, but others don't. some of them require separate power only if you're using a 4pin firewire and not 6pin.
a lot of usb or FW units have MIDI I/O on them, but you can also just get a separate USB MIDI device that is just as easily accessible.
even if the Q10 is not 20bit like I think I remember, the drivers of the Q10 would prevent me from using it because of limitation of the operating system. I know you said you've got XP and happy with it, but I am using win7 64bit OS and I'm very happy with it because it can use more than 3.25G of RAM for synths and plugins.
I"m not here to talk you or anyone into ditching the Q10 if you're happy with what you've got because I am not in the business of selling you something you don't want to buy. but there are alternatives.
BTW - since you have the signature that you do, please go over to my soundclick website and check out some of my tunes, especially my latest one.
http://soundcloud.com/beaglesound/christ-is-alive or the general site with more music
http://www.soundcloud.com/beaglesound/