As to power, what you have is sufficient for your system... it's when you introduce 3-5 more pieces of gear that it can suffer a little... and why I think the Haley would've helped regulate and prevent 'cross pollenation' of the current a little better...
OK... now comes the painful part... Please don't take this as offensive... trying to be constructive in a voiceless/toneless medium:
Your speakers have a lively or energetic sound that could use a little taming.. and the tubby and slow JPS cables sound helped.
I think the sound you are aiming for is 'clean and alive' which the Altmann delivers. I think the Altmann amp may be the right answer if that's the case... Especially if it was an integrated. The Snappers have a tubey harmonic distortion that leans just a tad to the grunge side, rather than the clean side to me. They do finesse as well... and therefore are good all-around amps... But I think you're attracted to half the amp's personality....
There is a balancing act of amp-to-cable-to-speaker in tone and detail and edge... etc. I would go with Grover Cables on less transparent systems... and Reality's on more 'lively' sounding ones. Right now I do a mix of Grover from tube DAC to preamp and Reality from preamp to amp.
The Squeezebox is a very nice little device to me, especially unmodified... but even modified I wouldn't use it for my hifi primary listening... But, that's for other reasons as well... When you have 2,000 albums, a single-line display isn't fun to me. Getting bitperfect data out of a PC is easy for me via USB or spdif but that's me. I prefer to attenuate analog rather than digital signals also for reasons you've recently heard... bits just get tossed... and you CAN hear it, big time in my opinion. The TacT is the only device I've heard that did a really good job attenuating digital... that was like magic.
If it were me, and I were you... the AR is the right sound for what I thought you'd like in a preamp. Every AR I've heard sounded fairly similar to Steve's... but with varying degrees of resolution/transparency. I know more about active pre's than passive's.. and I know you're eyeing the passive route... and I'd encourage you to go for it... because then I'll get to hear what a good passive can do.
I've gone astray a bit now... let's see... what was my point? Oh, you're on a journey, and quest for the sound you want... what you think you want today will change in a year. What was good last year isn't good enough this year. It's like an 'audiophile paradox'... haha... I keep this in mind so I'm OK with making major changes. One day I'll fall out of love with Piega's... It seems like blasphemy just to type that but who knows.... I don't know how many times I thought I was done. OK, I'm rambling again.
Finding the balance to get to your goal without breaking the bank is one of the hardest things I've ever done... But it was fun and rewarding in the end. I've found my happy-place with what I have... So much so that we're building a house around the core concept. So, it can also be motivating...
Thanks and hope this was somewhat helpful.
-C