For the power tubes, that one is harder (read: more expensive). I recommend the following, in ascending order:
3. Tung-Sol 7236 - clean and crisp sound, less bloomy or tubey (are those real words?), decent power and fast dynamics (compared to other 6080 compatible tubes). That last part is real; after spending a lot of time with the next two tubes, I noticed the speed right away with the TS 7236.
*Note: I have Sylvania 7236 tubes that don't sound half-bad; are close in sound, less expensive and less rare. Maybe try these - I haven't listened to these for a while?
2. Tung-Sol 5998 (or Chatham 2399) - the Chatham tubes are re-branded TS 5998, but my pair has somewhat different sound characteristic between the types, which might be a factor of wear. The TS 5998 is a favorite of many and presents a lot of bass and more "tube sound". IMO, it's a very syrupy tube with a lot of "bloom"; with the HD-650s, I think it sounds quite pleasing for some music, like warm guitar rock or female vocals.
1. Western Electric 421a - these have been described as the "holy grail" for 6080 compatible tubes; so far, I agree. Many believe these are identical to the TS 5998, of this I respectfully disagree. These tubes are now stupidly expensive on eBay. IMO, the Westys combine the best of the TS 7236 and the TS 5998 - that is, there is good bass and oomph, but with less bloom (i.e. less bleed of lower frequencies into the lower mids). The speed is good (not as great as the 7236, IMO), but what really separate the Westys from the pack is the clear, warm tonality. Seriously, with this glass, I can listen all night and lose track of the time.
*Note: I have a collection of 6AS7Gs from RCA (black plates) and Tung-Sol, but folks who know better usually advocate the GEC version, which is expensive and more rare; I have not done extensive listening to my 6AS7Gs, work gets in the way, so I with-hold comments on these tubes.