I have a pair of Hella Micro fog lights on a Nippy Norm's Autoswitch. I use these with dip for daytime running (three light points been shown to be good for recognition doncha know). They also act as dip most of the time in darkness and are perfectly adequate but not outstanding since they 'flood' the area in front of the bike. Well worth the money and small and discreet.
I also have a set of matching Hella Micro DE HID driving lights mounted above the fogs on a Migsel bar. Now these are the babies. They are hard wired into the main beam circuit and so come on whenever main beam is selcted or flashed. The result is err... awesome. Steptoe described a single HID spot as 'like a nuclear event'. I certainly wouldn't argue with that butbelieving more is better extrapolated to the nth degree went for the two. You certainly won't complain about a lack of light,

although as Andy points out you do tend to think you've gone blind when switching back to dip.
I went for the spots cos I suspect the reflector and lens combo on the standard lights is not up to much and upgrading the bulbs there (yes I did try that too) just sends more light to the wrong places. I reckon an HID bulb upgrade would be a waste for the same reason - with spots you can send the light exactly where you want it.
I paid £160 for a pair of HID spots (exaclty the ones Touratech want £200 each for) and about £40 for the fogs. Both were via German sellers on ebay. They come up pretty regularly.
This is them fitted:
HTH
LC