I shoot primarily in manual, but will switch to Av some times if light is changing, I also have a couple of custom modes on My canon S5 when I want additional saturation or contrast. I really prefer setting exposure by what I see in the viewfinder or screen, makes me analyze the whole picture and keeps me aware of what the cameras electronics are telling me.
I use M mode all the time because I like playing around with exposures and Depth of Field especially when comes sunset or taking pictures of windows to overexpose the light. Second option would be A for moving objects.
Depending on how fast the action is I usually use M mode especially for landscapes. When the action or light is changing all the time I will switch to Av mode and will rarely go over f4 because of sharpness.
If I'm using the 5D I'm in Manual mode 90% of the time. If I'm using the 400D then I'm in P mode 80%. I rotate between the other modes on both depending on the situation or shoot.
If I do shoot in Auto it's because I want to see what the camera suggests for a scene or I'm just lazy.
Janna,
For the wedding photography in particular, I am comfortable with 10mm-22mm lens because of groups and confined spaces and it also costs around $800.
For your question in particular, I used TAMRON and SIGMA, found SIGMA slightly better.…