I have tried many lenses on the Ep-1 and G1
What I recommend is the 20mm Panasonic as Standart lens, but the 17mm Olympus will do the job as well (here ad a external viewfinder from Voigtländer and you have a pretty nice camera).... For the legacy glass add a cheap 28mm 2.8 Canon FD when you like sharpness (Have tested many lenses in that range and the Canon was simply the best). I would skip the 35mm range as I do not really need the 70mm focal lengh. The 40mm Konica makes a nice 80mm. in the 45-58mm the best pictures I have seen on 4/3 where shot with the Contax G 45mm Planar (have the lens but no adapter :-( . But in this range is a lot of good cheap glass available. I like the Canon FD 50 1.4 SSC, Yashinon DX 1.7, Konica AR 50 1.7 and some Minolta and Pentax lenses in that range are pretty awesome and make some good portrait lenses and short teles. I also use a Helios 44-2 from time to time for sharp pics above f4. I skipped also the 85mm range but use a 105 2.5 Nikon sometimes. The M42 Super-Multi-Coated Takumar 3.5 135 is my favorite tele on the EP-1. I recommend really to test the lenses and compare them to others in the same focal range. Only this way you are able to find out what works good and what makes the lens special to you. In my opinion there is no need to put a lot of money on the table for very good picture quality. With the 4/3 system you are able to use almost any lens. I sometimes buy a lens below $5 and I am very impressed about the quality it delivers. It is also about size on handling, especially if you will use the lens on the Olympus 4/3 body.
Buy cheap -> test -> sell or keep...
For instance I was unimpressed by the 28 3.5 Zuiko, the 50mm Zeiss Pancolar, all the 50mm M42 Tessar, MIR-1B 2.8/37, even if those lenses have a good reputation.
If you like it wide open and spent some cash...an old German sharpness ranking of f/1.2 lenses wide open starting from best:
• Pentax SMC 50mm f/1.2
• Nikon Nikkor 50mm f/1.2
• Canon FD 55mm f/1.2
• Minolta MD Rokkor 50mm f/1.2
• Canon FD 55mm AL f/1.2
• Yashica ML 55mm f/1.2
• Olympus Zuiko 55mm f/1.2
• Nikon Noct-Nikkor 58mm f/1.2
• Leitz Noctilux 50mm f/1.0
• Konica Hexar 57mm f/1.2
Sample of the Canon FD 28 2.8 below...