We are living in exciting times when it comes to amp choices. Some great tube options and a couple of fine digital choices have already been mentioned.
Let me put a word in about my extremely positive experiences with another new to high end technlology - chip amps.
This months 6 Moons has a review of the 47Labs Gaincard that started the chip amp movement here:
http://www.6moons.com/audioreviews/47labs5/gaincard.html .
They also reference the Patek version of the amp - half the price and at 50 wpc rather than 25 it may be a better match for the XLs if you play your system loud.
The amp I am now enjoying my XLs with a similar amp, not really a "gain clone" at all but a new design by Mauro Penasa that uses the LM3886 chip driven by a LM318 op amp. (A DIY kit from twistedpearaudio.com) .
I was previously using a Primaluna tube amp, but really like the chip amp better. Its quicker, more detailed, but every bit as sweet and musical. Really remarkable for the price... well, remarkable period. All of these amps measure really well on the test bench. I am convined most of the differences we hear are due to the specific interaction between the amp and the reactive loads of the particular speaker. I hear a real synergy with the XLs and the twistedpear chip amp. I think the sum is greater than the parts.
I hope that your take away from all of this is what has been mentioned earlier. The XLs are very amp friendly. Easy to drive and they will show off the best of most amp designs. However, their resolution is high enough that I promise you'll hear real differences between these amps. I think the best advice is to try to audition a few different amps, and preferably even different technologies before you decide. It well worth the shipping charges, or trips to the store to find the one that works best for you.
BTW, you have a fantastic CD/SACD player already. I would probably pick the amp first and then change the disc player after that.
