You haven't mentioned if you're limiting your choices to two-channel processors.
Also, what's your price range?
Some of the quality multichannel pre/pros I'm aware of are the Marantz AV7005 (soon to be replaced by AV7701 and AV8801) and the Integra DHC 80.3 (there's an Onkyo equivalent, but I can't remember its model number). They list at about $2K-$2500 but are readily available for less. McIntosh and Arcam make some, too, but at substantially higher prices.
Of course, the receiver proponents reasonably claim that you can get equal audio quality with any modern receiver, but there are other reasons for selecting a pre/pro instead.
Edited to add:
All modern pre/pros apply 2.0 -> 2.1 processing in the digital domain. In other words, while you can use analog connections, they'll digitize them again. In most cases this won't really make any audible difference (unless something is broken), but many people are unhappy about this. If you feel strongly about doing bass management in the analog domain, you'll probably have to consider buying pre-owned pre-HDMI equipment. The Marantz AV9000, for example, could do it, but only for a fixed 80Hz crossover.
Marantz SR7009 avr + MM9000 amp --> Atmos 7.1.4
Fronts=NHT 2.9+AC2, FH+TM=DefTech PM1000, LCR+TM amped