What size room are you going to use them in?
Are you also going to be using a sub?
Any room treatments?
I have used quite a few different amps with my many pairs of 626Rs. At the Midwest Audio Fest I used a 75 wpc tube amp (two EL-34s per channel) to drive the 626Rs full range while using a larger sub to fill in the bottom octave in a fairly large room.
I have used digital amps, most recently a pair of Spectron Musician III. They were VERY clean and tight. Also $15,000.00 a pair

The "Ultimate" amp would be the one you like the best in your room. No one can tell what that may be.
At RMAF this year, I will be using a pair of 626RSDE with Eastern Electric M156 tube mono-block for the mids and highs and a Levinson clone solid state amp for the woofers. The tube mono-blocks are 160 watts each and the solid state amp is 250 per channel.
The amp selection will depend on what type of sound YOU like. Tube, transistor, or digital. Each has it's pluses and minuses.
I would suggest a minimum of 50 watts for full range use. I did use a Response Audio Bella Extreme 3205 (50 wpc) to drive a pair of RM-30s at RMAF a couple of years ago. That sounded very good.