Is the Nikon SB600 Flashgun compatible with a Nikon D300 Camera?

Is the Nikon SB600 Flashgun compatible with a Nikon D300 Camera?

Of course it is. Completely.

The Nikon SB600 is a perfect match as I use it regularly with my Nikon D300 DSLR and have used it with D200, D70, & D50 cameras.

It has price advantages over the SB700 and SB900, while it has a motorized zoom and sideways swivel (necessary for "portrait" oriented shots) that the SB400 doesn't have.

Though it's discontinued, it's till my favorite Nikon flash.

Yes. Both in hot shoe and as a slave flash. Good choice.

Another vote for this combination. Use it extensively, still meaning to get a second one but somehow I never seem to spend enough time doing studio shooting to make that worth it.

Yes absolutely! I have a D300 and 2 SB600's (plus other 'third party' flashes).

You can use it on the hotshoe in manual or TTL mode. If you want to use it off camera you have 2 possibilities;

1) Use the Nikon CLS wireless system. The pop-up flash on the D300 can act as a commander to trigger the SB600 in remote mode wirelessly. You can shoot in TTL (ie auto flash metering) or manual, AND change these settings and power output of the flash 'on the fly' using the in camera menu (you don't have to go over to the flash to change it). The signal is optically based, so does have line of sight/range limitations.

2) Use radio triggers (like RF602's). The advantages are that you don't use the pop-up flash. The range & line of sight issues are removed (as it's a radio signal - you can even fire the flashes through a wall) which improves reliability. The disadvantage is that you don't have TTL flash - you set the power output manually, and you have to do this on the flash. RF602's cost about £27. The other advantage of THIS system is that you don't need a Nikon flash - any cheap manual flash will do. For example, the YN560 has better specs than the SB600 (in fact it's comparable to the SB800), but at £60 costs at LOT less than an SB600 (£220).