I have the Olympus E-1 with the FL 50 Flash and the large battery.
I also have following the lenses:
11-22mm 2.8-3.5
14-54mm 2.8-3.5
35-100mm 2.0 all the way through
50-200mm 2.8-3.5
If I only could have 2 lenses, I would have:
14-54mm and 50-200mm both with 2.8-3.5
By 35mm standards with both lenses, you would have 28mm to 400mm
I use all my lenses, but these two, I use the most.
I know they are more expensive, but I know good fast glass cost money.
With the 2.8-3.5, I can use lower ISO and I can blur backgrounds when I want a more isolated subject.
If you live in America, I found the best prices at B & H Photo.
http://www.bhphotovideo.com/Everything I purchased from B& H, I also received a rebate directly from Olympus.
Hoped this helped.