Any program that is compatible with AHI will let you use the AHI Paula 14bit HiFi Stereo mode.
If you you a doublescan screenmode (31khz) you can then crank the audio frequency from 27KHz to 44.1 or 48KHz which greatly clarifies the sound most of the time.
Maybe these sound comparisons I made for someone else will give you an idea of just how good Paula can sound with the right settings and software.
http://lavaburn.com/files/amiga-audio-comparison/The files will stream if you drag and drop the links into Winamp/Foobar2000 etc.
This is a 22 channel (IIRC) XM module (FREETRUE.XM) playing on DigiBooster using various AHI modes. Any clicks and pops are DigiBooster's fault; I don't think it has any volume ramping to smooth out the samples.
I used the CyberSound 14bit calibration tool to prepare the calibrated modes.
The Hifi 14bit 48KHz mode with calibration sounds very nice if you can use it (I have an 060/50 and lots of fast ram so I dont notice any lag etc - your mileage may vary).
The difference between 8 and 14bit calibrated is very significant - notice the hissing in 8bit mode as the samples are cut down to 8bit.
But it should help you decide if you need a sound card or not. I'll be sticking with Paula for a long time yet, unless I find a zorro sound card cheap. :-)