Audio Bit Depth/Sampling Rates, How to choose the best one for your task at hand. Options

Ok, so there are dozens of cards and systems out there that will allow you to record in 24 bits and 96 khz. But as far as I can understand, unless you are creating/recording all your samples yourself, ultimately you will be faced with having to work in the lowest common denominator of all your sound sources.
For example, I sample extensively from CDs and there are dozens of CDs being produced for this purpose, all/most of which store audio in the standard CD format of 16/44.1. Moving files to higher sampling rate environments causes changes in playback speed...how do you get around this?
Do you pitch shift everything and make it right--sounds like a lot of work. Or do you just live with it and compose in 16/44.1. If that's the case, then if your sources are CDs, etc, what purpose do DA cards serve? None would be my answer, but I don't have a lot of experience in this regard--yet. So I put the question to all you experts out there...how do you get around the problem of the lowest common denominator?

[Synthetic]

This is a very good topic. I have been reading lots of interviews and articles dealing with this subject lately and this is what I have learned.

Ok, bit depth... CD's use 16bit audio right? So it makes no sense to create audio in higher bit depths such as 24bits right? Well, not exactly. What I have learned is that even if you record and use 16bit for your audio tracks... you might be only get actually around 14bits of good audio due to the analog converters and such in the processing chain. So I have read that it is good to use 24bit to get more headroom and better signal to noise ratio and then convert back down to 16bits in the mix down. This will give your audio tracks a more true 16bit sound with better quality. I read that Crystal Method used 16bit on Vegas and was not real sure about using 24bit until an engineer had let them compare their Vegas recordings with some new 24bit recordings used in Tweekend. They were hooked immediately. So I would say use the larger bit depth if possible.

Sampling frequency... CD's use 44.1khz but now there are much higher resolutions. I think the same ideas apply here as they do for bit depth. Higher sampling rates will give an overall better quality recording but then reduce in the final mix down for CD use. I have read an interview with the producer of Staind's latest CD and he mentioned that he uses 44.1khz as opposed to 48khz though simply because he couldn't tell much difference but 96khz may be much more different than 44.1khz.

And it all depends on how picky you are about your sound. If you are using lots of fuzzed out sounds or distortion... then it may not make a difference if you use higher bit depth or sampling rates because the listener may not hear the difference. And yes.... when working with samples... its much easier to just work everything in 16bit (44.1khz) to keep samples from speeding up and such and you are not going to be able to improve the sound of samples in higher resolutions if they have been recorded or dub from lower resolution material.

I do all my songs at 16bits and 44.1khz but sometimes I might record one track of an instrument playing at 24bits, 44.1khz in another sesssion and then bounce it out at 16bits to import into the original song session just to get that little extra sound quality. So I hope this helps.