In theory, sample rate conversion may cause errors in the audio files. THis is the same logic that records at 88.2(instead of 96K) for a final product CD. The math to convert form 88.2K to 44.1K is simple, vs the math to convert from 96K to 44.1K. My philosophy is simple. If the end goal is audio(CD or uploads) I go 44.1K. If the end goal will be tied to video, I go 48k. In either case, I always record at 24 bit and dither the final 2mix during mastering (even if its nothing more than dither and Waves L2 for a rough CD. I bounce to disk at the original sample rate and bit depth. Any conversion or bit reduction gets done in a separate step in WaveLab(including mp3). Now, having said all this, if your ears tell you that 48K sounds better, then go with it(I have yet to have a client mention it).