How much difference in sound?

Hi Gary.
I would upgrade the speakers first. You might then find no need to upgrade the pre and the amp.

Gary...

If you are indeed sold on doing the amp first... get a popular one that will hold it's value and it's ability for re-sale.... given the budget you initially provided. Later on you can sell it and take one more step into ampland and be near done there... for all intents and purposes.

Also keep in mind this... amps only can increase the signal amplitude they recieve. They don't purify it, sweeten it or improve upon it. Whatever the integrity of the signal it see's is what it will increase... Better amps will convey whatever the upstream devices provide. Clearly usually with greater detail and resolution.

Consequently, if the info is off somewhat or somehow, the resultant amplified info may not be better and can be less acceptable in fact, as it will reveal more so the quality of what it sees coming into it.

If there's any chance for you to in home demo one or two, by all means do that first... just to see what's going to happen with this upgrade.

Good luck

Mr. Blindjim has nailed it for U. I say start with a better cd player. There are very good players at different budgets.
I think you need more information from your source, just to be able to tell which amp,which speakers--

Any suggestions on a cdp that will be a nice piece in the system if I do choose to upgrade the amps in the future?
gary