I have a Delta 44 and it does a great job. In a desktop, if you only recorded on 1 computer, I don't see why anyone would opt for a USB or firewire solution over PCI.
I use the Delta 44 also and think it is a Great Card and very easy to use and it has Twice the Inputs as the FastTrack USB....
If you need the Pre-Amps that the USB one has then get a small Mixer which will also increase your Inputs and Give you the XLR and Pre-Amps but if you are mainly recording Guitar then you can Connect the Send from your Amp into the Delta 44.....