I must admit my total lack of knowledge when it comes to flash units. I am considering buying a flash to use with my nikon D40. I plan to use it for portraiture/general indoor photography. I would also like to play around with using a flash to help bring out foreground detail in landscape photography. Would be nice to be able to fire the flash off the body too if possible. I may buy a D5100 or D7000 in the near future. I also have no problems buying third party. Any recommendations? Fire away (pardon the pun).