Well you can go to a lighting professional/store in your area and ask for their opinion, ask to speak to experienced tech on the phone for one of the online suppliers. But none will really be able to tell you exactly how much light will satisfy you.
Do you have dimming control on these lights, because that will limit your choices. If R30, are they surrounded by metal or plastic outer cover of the fixture, or do they just screw into a somewhat bare socket? More of a bare socket, or a cover that can be removed would allow any size reflector to be installed (depending on how much the larger size/asthetic offends your senses [img]/ubbthreads/images/graemlins/smile.gif[/img] ).
Perhaps a slightly larger PAR38 (again, without seeing your fixture, we can't tell how much room there is to install larger sized reflectors) might give more throw?
If you are using incandescent or halogen now, you are much better off buying more expensive full spectrum fluorescent, because many people (like myself) hate fluorescent tubes 'off' colors and the fact the most regardless of the temperature ratings have very poor color rendering(CRI) capability.
jtr1962 had linked to this full-spectrum supplier before, but while they have a 26w 1800lm(equivalent in total lumen output to the new higher output Halogen 120w PAR38 lamps) version, the detachable mirrored reflector is 'open' ended, compared to many that have the actual spiral tubes covered with clear plastic of semi-opaque covering. This means a bit more glare from the light. Note that of these CFL bulbs/reflectors are said to be fine with 'ventilated' fixtures. If you have your track lights with plastic or metal covers around the screw-in base socket, this is in effect a semi-closed enclosure, considering the BD (base down) arrangement. In other words, it is likely the ballast will overheat and fry the inner components long before you get anywhere near the rated lifespan!
http://www.fullspectrumsolutions.com...orescent.shtml
A very slow site that is all behind secured link (at least for me on dial-up) which has many different brands of CFL's and somewhat poorly organized is this one, which lists 5100k lights, but does not give the CRI numbers:
https://secure.tcinternet.net/buylig...cflfloods.html
www.buylighting.com