No problems for me either - I might get a strange look every once in awhile, but that's about it. I do try to limit photography when in true, international, first class cabins. I kind of regret this looking back, as there are many spectacular shots I could have had in places like the UAE flying in over the gulf and such.

Otherwise, I will usually limit it to shots out the window if in Y, J, US domestic F, and a few cabin shots here and there if I am one of the first to board and I can avoid getting mugs in.

I always keep the flash off when taking photos on the aircraft. When taking photos at night, the only way to get a decent shot is with the flash off.

I enjoy getting photos of the scenery, especially on departure and landing, photos around airports, other aircraft, unique aircraft, etc. I also like getting shots at sunrise, sunset when going through cloud layers to get the different colors of the sunrise/set and clouds. I will take photos of the IFE map from time to time to get a point of reference in (can be hard to get, depending on lighting). Thunderstorms at night or dawn/dusk -- even during the day depending on the lighting & cloud colors can be impressive.

Sometimes I'll keep the camera going and just do photo after photo -- you may get 10 or 20 average ones and then you get that one spectacular shot be it a lightning strike or another aircraft landing next to you in perfect focus.

From flights at altitude, I keep my eye out for interesting landmarks, mountain ranges, etc.

Sadly, I've lost many of my photos from over the years (I believe they're on a few CD-Rom's between moving, hard drive issues and such) - but I've been very aggressive with making backups and keeping backups the past couple years - especially as I've upgraded to better, higher quality cameras. Today I now make daily backups of all machines on my home network having learned the hard way.

I am in the process of getting a collection of aviation photos online with more recent photos, plus photos I've been able to find from past years.