I don't really see the problem with altering in photoshop. It's the same concept as a traditional darkroom. Course, I used to be very wary against anything beyond a simply level / saturation fix but I got over it. Photoshop is a tool to enhance certain qualities or correct unintentional errors in photos. It's up to you whether you want to use it or not. However ANY corrective editing is seriously frowned upon with any photojournalism work. But for the sake of art or personal aesthetics, go nuts. The only problem I have with altering photos is when they do it to a point where it doesn't even look realistic anymore. If it was photomanipulation then fine, then label it as such. Also, running a photo through several Photoshop filters is not appealing to anyone.
Hm. I don't have too many experiences with filters. I could just go into photoshop and do all that stuff ;p. I have a UV filter basically for lens protection and I have only used a spot filter which works pretty swell.
Hm. I'm pretty apprehensive when it comes to photographing around people. But It's like, if I really want the shot, I'll go for it. I've asked several people if I could take their pictures and I've only been denied maybe 3 times. They were only attractive from behind or from the side anyway so no big.
I used to take my SLR with me everywhere. Not so much these days. I used to lug around my Polaroid but the bag I carried it in got busted.
Jam it back in, in the dark.