This is a very interesting conversation.  Sometimes with bass, and any other part for that matter, "boring" is less relevant.  If you deconstruct the whole, parts might seem disjointed and boring, but sometimes simple goose eggs are needed to anchor the mood of a piece, which might be more important than its cerebral engagement.

  I've been a professional bass player (rock, pop, country, etc.) for some time, so I come at writing w/virtual instruments more from a songwriter's point of view, coming up with interesting chord progressions (usually on piano) and then filling in the melody/harmonies etc. around them.  This approach seems to work for me, but it's got shortcomings.  For one--it's too easy to get caught up in block chording.  I like what William said about writing for smaller ensembles.  You can't hide behind a great wall of sound to keep it interesting.  Barber's Adagio was written for a string quartet (?) but it certainly holds up just fine with a full orchestral string section.  That's my goal.  I've got a long way to go.

  One thing I've found about bass--  if the parts are just being used to anchor the harmony, it's best to pick and chose where the bass parts come in, and use a less is more approach.  Of course a live bass player wouldn't be too happy with playing nothing.  Ah well. 

I don't have much to add here, since some of the ideas are useful. But composers wanting to write interesting bass parts should take into account SALIENCE (for example, "moving lines" tend to be heard). Alan Belkin has written about salience in a sensible way, (his books can be consulted and downloaded online for free, and his site has got useful things).

Also consider that salience by itself may not be enough...protagonism may also be useful.

TIP: if you want to find descriptions of bass parts, or similar, copy and paste the following in Google:

"bass part is" + double bass

[8-)] Does anybody find this useful?