[citation][nom]williamvw[/nom]not everyone has Line In capabilities on their PCs[/citation]
Not sure what stuff you're smoking there, but I have yet to meet with a notebook/netbook/desktop that didn't have a line-in or mic jack. Every computer has one, since audio is now a requirement on PC's.
I've been converting analog audio to digital for more than 10 years, using Cool Edit Pro as my preferred software, and a good 3.5mm audio cable. It's the only software I use and the only software I need, as everything else I've tried is a crying joke. Everything from noise-reduction, hiss/pop removal, normalizing, hard-limiting, dynamic range expansion, parametric EQ, gap removal, down to bit-for-bit cut/paste wave file editing I've done - and I can load and save WAV, MP3 and WMA files in any bitrate/sampling frequency I desire. Best software purchase I ever made, and it only cost me $25.
For vinyl rips I still use my turntable/amplifier and get standard RCA out. As for cassettes, I have a soft-touch full-logic dual tape deck that I use to play back my mountain of type IV tapes, all recorded with Dolby C and S NR. They sound damn close to anything even my hyped DAT recorder could do back in the day for sure.
As for itunes rips, I just use the stereo mixer as my line-in source - play back on itunes and record with CEP. It's the easiest way to un-DRM your music, and a great way to record streaming audio from sites like Pandora. (Free music anyone?) You can even connect computers together to record from one to the other, like you would in the old days with two tape decks.