There are many variables, but a lot of us here love the combo of tubes on the pre and solid state to do the heavy lifting (amp). It's a nice yin/yang. Some, like AC member George (zybar) have great sound the other way, with a nice little ss pre and a very hi-end tube amp. That being said, you already have tubes in your signal path, and there are many nice ss pres that are not clinical and cool; pre's like Wyred4Sound and others are almost tube-like. As you move up in $$ there are nice tube preamps that have a neutral quality, too....like the Modwright LS 36.5. net/net, there is no longer a huge dividing line between the tube sound vs the ss sound. Sure you can find each end of the spectrum, but the middle area is much more crowded. What's your budget? What are your speakers (or mare importanty, describe their sound)?
In any event I would not buy a preamp before trying it in your own system. System synergy is what it's all about. It's like a recipe, and that one ingredient that you'd think would sweeten the taste actually reacts almost counter-intuitively. It happens all the time. Try a few at home. 
Oh...and Welcome to Audio Circle!! 
Budget: I don't think I could swing any more than $1500. That being said this will end up being the most expensive single piece of gear going in. My single ended buddy says a good front end is worth it. I happened across the Rogue's Perseus and think if I could find a used one I'd be a happy camper.
Speakers: As I said in the original post my system is budget, double duty. To that end I have Axiom speakers. M22's Mains, VP 100 Center, QS8 surrounds, and a Hsu STF-2 sub. I've never really thought about how my speakers sound. I do know what I like though. I have become interested in more acoustic based recordings. Especially string based, folk. As well as good vocal stuff. What I understand to be right up a tube's alley. I also am becoming interested in Jazz, ala Davis, Mingus, Monk. This is mainly because of my 2 channel buddy, but he is running mainly vinyl and I don't think I'll ever achieve the sound I hear on his system. Not even close callings it apples to oranges. Unless the apples cost WAY less than the oranges.
As far as tubes currently in my signal path with the Nixon, I wonder. I have rolled a tube and definitely prefer running through the DAC than through the dedicated stereo out of the base Oppo-83. I did pick up the Nixon to get a tube in there, but I understand it is being used as a buffer. I'm not sure how that plays in to things. The Eastern Electric DAC uses a tube on the output side. Will this impart MORE of a tube feel? I am also interested in the Sabre chip due to its promising specifications.
I hope this info can help you out there steer me in any sort of direction. I also wonder if I put this in the right forum. This is all aminly two channel stuff, but I really consider my system dual purpose and was hoping to get input from people with similar situations. I apologize if this belongs somewhere else.
Thanks for the welcome and I look forward to any advice out there.
Sips
