A dimmer is not only possible but strongly recommended. You might even
want to look into dimmers that can be controlled with a remote. (Big
cool factor and $!)

Check your spacing. If you have a 40d beam (Sylvania
100PAR38/CAP/IR/FL40 120V) then at 5' from the ceiling (table height)
you'll have about a 4' pool of light. Diagonally between fixtures will
be about 7' so there are little dark spots all over. Any smaller beam
angle and it's worse, unless all activity happens on the floor. ;-)

Paul's comments on lighting walls and the harshness of recessed are
quite accurate. But all that gets into designing lighting, not which
bulb to use. Look around at other rooms in houses and elsewhere and
you'll start to notice that there is a lot more to lighting than- "Is
it bright enough?"

Richard Reid, LC
Luminous Views