I say get a digital board ... but for sure know what you're getting into first. At first glance it doesn't look like
the TM-D1000 has any analog channel outputs, so you have to have another plan to get your signal into your PC if you have an multi input analog card now. You can get an optional TDIF card for more money (or lightpipe ... but I've heard rumors that Tascam digital mixers are problematic with this ADAT format ... just rumors though) ... As mentioned above, this would kinda force you to get a soundcard that would accept the same format.
Also, there's only 4 XLR inputs, which leads me to believe that only those would have phantom power (that's how it is on my board anyway) ... if you want to use more than 4 condensor mics you're looking at needing an outboard phantom power unit (or battery powered mics) and transformers anyway.
Bonuses of a digital board ... and some may argue with some of these ...
onboard effects, dynamic processing on every channel, ability to save a snapshot of your mix (really big timesaver), etc. I think while the effects and dynamic processors on these digital boards may not be as good as some outboard gear, having them inside your mixer with for sure save you some money ... if only for the short term.
I think I remember seeing this board on sale at musiciansfriend.com for around $500 ... which is a very attractive price ... but don't forget about the extras you may need.
Good Luck!