which tubes for which genre ?

I have to agree that SET amps will not satisfy you playing rock music. There are some with higher power outputs that MAY work with an 86db speaker, but- most tube amps output less into 4 ohms than 8(the audience is a nominal 4 ohm load). You could get away with 40-50 push/pull tube watts, if you're not into rocking the house(like a pair of modded Dynaco ST-70's switched to mono). There are some good hybrid amps(tube driver/MOSFET output) available on the used market that would give you the option of trying different tubes, but would still have plenty of solid bass and over 100 watts per channel. An excellent example with 250wpc: (http://www.audiogon.com/cgi-bin/cls.pl?ampstube&1230558327&/Audio-By-Van-Alstine-Fet-Valve-Ultra-550)

Your speakers are the limiting factor, not the SET amp.

Make no mistake, DHT Flea Powered SET amps, be it 2A3/45/300B/171A/845 etc. can do rock and can do it very well. They can give you details like you have an electrostat speakers, and tranparency like a ribbon base speakers with bass as if you have enormous stereo subs in your room provided that your speakers can produce them and have the right sensitivity.

In short, yes, SET's can rock! The question is, can your speakers handle low powered SET's and do them justice?

Waste of money pal especially for rock...
And What's the point havin' amp only for voice or small acoustic bands???
Anyways, one of my favorite tubes are AudioResearch VT100 and I like it with any type of music. It can rock, sing and jazz, just give it the right speaker -- yours are but there's always room for better match...
Also you can research VTLs and Quicksilvers that are more affordable options

Matter of fact: A pair of VTL 300 Monoblocks would be a perfect match for your speakers(if you have the room). Whatever load they are wired for will receive their full rated output. Just be certain they are internally connected for a 4 ohm speaker(easy). WON'T break the bank/WILL rock the house! Very fast slew rate for a tube amp(more detail/accuracy, better imaging, great soundstage) and excellent bottom end.

thanks for the advice guys, let me start from the beginning do the audience 42's match better with ss or tubes ?