[Updated for 2012]:
Older materials were recorded on an Akai GX-F31 cassette deck, Dolby C, on Maxell XL-II, TDK MA or Fuji MR tapes (with some exceptions). From the tape deck to the computer at 44 kHz 16 bit WAV, minimal processing in Sound Forge and burned to Verbatim or TDK CD-R. Cables: Ixos, Monster.
Wherever indicated, some materials were ripped directly from internet streams (by RealPlayer) or recorded directly to a laptop via an external Soundblaster sound card (with mediocre results, though), so I abandoned that route.
You can't get rid of all noise (hiss) without detriment to the music. After all, this is a radio broadcast, not an audiophile recording!
Currently I record the radio signal directly to a Sony HDD video recorder, rip the audio from resultant VOB file to WAV (48 kHz/ 16 bit), process with Sony Soundforge, resample to 44 kHz/16 bit and convert the WAV to FLAC.
I try to preserve the concert atmosphere in my recordings - with all coughs, tuning of instruments between individual parts of a work etc., unless the program was not broadcast live and was edited by the radio people.