I would personally recommend getting a Traynor YCV40 WR. I own one of these amps. They seem to go around $600-700. They are extremely versatile amps. They come with a Celestion Vintage 30 speaker, which is one of the best in my opinion, and it is very class looking.
I retubed the amp with the regular retube kit from eurotubes.com (go to shop online, they have them there) after about 8 months of playing it and it sounds even more amazing than it did when I bought it.
If you like EL84 tone, then they have the YCV50, but I felt that the 40 had a smoother tone with its 6L6's and is my personal favorite amp.
Clean Channel- Very smooth and with the bright switch engaged is can be shimmering and chimey, perfect for a slow arpeggio or chord progression. Without the bright switch engaged, I think it is very well suited for Jazz/Blues, and you can dig in to get a little overdrive with the volume over 3.
Overdrive Channel- Creamy distortion with tons of sustain and clear harmonics. You hear every note in open chords all that way up to gain level 7. It can go from bluesy to rockin in a second, and the boost switch adds some mids and volume, to let you really shred up the leads.
I highly recommend this amp.
ONE MORE THING:
http://www.musiciansbuy.com/mb/item.asp?ic=YCV40WRKIT has it for 619 instead of 669. If you want to buy from MF you could get them to do a price match (Thats what I did).
REVIEW SITES: www.harmonycentral.com (its currently down, along with half of the guitar community but it has the largest amount of reviews I have ever seen)