Olympus FL-50 Flash

Decent flash, but overpriced compared to Nikon's SB-800. Since the FL-50 is the only flash that will give you high speed shutter sync with an E-1, you really don't have much of a choice. That said, it performs quite well. Plenty of power for bounce and outdoor fill. With the 14-54f2.8-3.5, it zooms automatically at 14, 18, 25 and 35, but only when the flash is locked in the standard forward facing mode. Once you tilt it, it zooms all the way for max power. Refresh times are best with 2500 Nimhs-AAs (about 4-5 seconds at full power). I've heard that the optional power pack cuts that time in half. The flash is very large. It balances well on my E-1 with the grip attached. Without the grip, the Fl-50 makes the E-1 top-heavy. I think the smaller FL-36 would be better for E-1s without the grip (albeit with less power and slightly longer refresh times). At $400, this lens does not offer wireless capabilities nor quick release shoe mount and has a build quality that lags lower priced flashes from N and C. The previous FL-40 had much better build quality but is a poor match for the E-1 (no high speed sync). It's your only choice if you shoot Oly. Must make a lot of money for them.

More power and faster refresh times than your only alternative, the FL-36

Expensive relative to N and C
Build quality lacking for price

Olympus FL-40
Nikon SB-800, SB600