Given my AMP and DAC, which preamp?

I am about to receive a Dodson 218 DAC. I have a Pass X250.5 amplifier (please view my system). I essentially have a one source system (hard-drive based, digital). What I am wondering is, what preamp to get? I am wondering whether a tube pre would work well or maybe I should go with a matching Pass Labs preamp? I also can't rule out some kind of volume control like the Django. I would really like to hear from those with similar systems to my own. Thanks for your time,
How about a modded Squeezebox II directly into the Dodson (nice DAC BTW). No need for a preamp unless you have something else to plug in.

Pardales, if you look at my system I run Pass LabsX-350.5 with Threshold SA-1 monoblocks to bi-amp MG20r's. So, I'm a big fun of Nelson Pass's designs. I would suggest you audition either a Placette passive line stage at $1500.00 or the reference dual mono active linestage at $4500.00. They both sound great with Pass gear and Guy Hammel, the owner and designer, is a gentleman and a pleasure to deal with. Both linestages are outstanding and great bargains at there price breaks. I auditioned over seven pre-amps, both tube/solid state, and thought the Placette active was the best for my ear's. It replaced a reference ML-32 in my system that cost almost $10000.00 more! I did not change for $ reasons, but because the Placette sonicly out performed the ML-32, along with the other pre-amps I auditioned. You order directly from Guy and get a 30 day audition time period, with full return minus shipping if you don't keep the piece. Since, there's no middleman, the prices of his pre-amps are true bargains, all the money goes into design and quality parts.
I had the X-250 with an Audio Logic DAC. I tried a ton of other DAC and preamp combinations including the X-1 preamp. The X-1 is one of the best SS preamps on the market. That being said, the X-1 does not sound like a tube preamp. The tube preamps I tried had a different presentation in the mid range, but some lost the dynamics, bass slam and extention of the X-1. AS always, presonal preference and sonic trade offs. I will say that the Tom Evans Vibe was a excellent sounding preamp with the X-250 as was the Sonic Euphoria passive preamp. Could have lived with either one for a long time. There was VIbe selling on Agon a few days back for dirt cheap, it is that good (not mine).

Hope this was helpful, email me with any questions.

Happy Listening.
I second the Placette active unit or the First Sound Presence.The Terra Song (up for auction) was dependable and made tube comparisons a breeze.
Awesome suggestions, THANK YOU! Please keep them coming. Part of me thinks that I am really after is a high quality volume control with one, maybe two inputs. I do not need phono or tape, or any of the other functions of a full- function preamp. The VIBE sounds like it might be the ticket. Any experience with other volume controls like the Django?
I went through a number of tube and solid state preamps and ended up with a Placette passive for several years. I upgraded to the active and have been totally pleased. I'll second TeaJay's recommendation. The Placette active is the best preamp I've heard.
Played a hunch and went with the new Modwright SWL 9.0SE. It is burning in as I speak. Thus far, I am blown away.

I could not go for the Placette as I like to have a volume knob to turn; also, the look and how I interact with the equipment does matter to me (wish it didn't some time, but alas).

Thanks for your suggestions.