The OEM bulbs that come with the bike are Philips H4 Halogens - they are very good.
Note that any bulb that promises more lumens with the same wattage is lying. There are some potential psychological gains that can be realised by choosing 'blue' bulbs because the eye can be more sensitive to the bluer hues - but those are realised by filtering out the reds from the spectrum, not by increasing the light output. With 'conventional' technology it is in the watts and in the filament. 9003 bulbs (and presumably Nightcutters and the like) achieve a lot of their intensity by being more careful in the placement of and size of the area lit up by the filament - the tighter the ball of light, the better focused it will be on the road, which means more of the bulb's light where you want it. The drawback is that the heat is more concentrated, which often leads to premature bulb failure (like the SilverStars).
If you choose to increase the wattage, you might want to consider a relay and harness to take headlight power directly from the battery and to preserve the bike's internal relay.
As it happens we lose a fair percentage of power in the stock wiring - when the modulator is flashing the marker lights dim perceptibly - that means that the headlight IS losing juice - and a higher wattage bulb will lose MORE juice. Bulbs are very sensitive to voltage, so a heavy duty harness is a good solution even if you don't change your bulbs out.
Changing the headlight to HID has some fallout; First of all your lighting is not going to be legal. Second, if you run a modulator now, you won't be after you swap out the lighting. On the other hand, conventional HID technology consumes 35 watts per bulb compared with 55 or 60 for the OEM lighting, so you can save some watts.
However the reflector in the FJR is not designed for HID bulbs and most conversions therefore have issues with dazzle and light spill. The problem is primarily with placement of the plasma ball, but also the size of the ball itself puts it outside of the optimum spot for the reflector.
I have Hella Micro DE Xenon (true HID) driving lights mounted on Garauld's brackets under my mirrors. They are very small, quite effective and I happened to find myself a set for an excellent price on Ebay - Ballast placement is an issue - though I saw where one member simply extended the high voltage wiring and tucked them under his seat - not sure how much my Autocom would like that, mind you.
Slim ballasts are available, though they tend to suffer from premature failure - probably the Chinese took lots of design shortcuts, not to mention that the heat they produce is concentrated in a smaller space . . . but they are easier to stuff into the confines of the Gen-II's tight front end.
I do have a couple of photos on my webshots page. Here's one . . .
Note that the headlights are ON in this picture.