Tough one Alf. How much flash photography do you do and how important is it that you get the flash off camera?
GNs aside, there is nothing wrong the the 36R - I had one for my E-510. If you're worried it might be low on power, snoot it, bang on a grid or use an 80/20 and force the light where you want it. It's more than powerful enough for most work.
Assuming you need off camera, wireless, flash connectivity you've got several options. It then depends in you need/want to maintain TTL functionality. If you do, the FL36R or FL50R are your options. The only significant downside I can see is that they're both very expensive for what they are. The 36 is pricey and the 50 - wow! I thought the Nikon SB900 and Canon 580EXII were expensive!
Apparently the
Metz 58 AF-1 and
58 AF-2 are both capable of running Olympus dedicated IR with full TTL as well. They're still fairly pricey (£250 and £285 respectively). Sounds to me like you're likely to want to avoid Metz though. What model do you have?
You're other option is much cheaper but you will loose TTL. You could get something like the
Metz 44 AF-1 (£145) or the
Nissin Di466 both of which are 4/3 compatible.
Mounted on your camera you'll get full TTL and all the normal stuff. If you need to trigger it remotely, do it with something like the
Strobies iSync 4 or
Hahnel Combi TF (£45 and £60 respectively) and you're sorted.
These would offer you much better remote firing as they're capable of radio triggering. Using IR means you need line-of-sight transmission which is often restricting if you're getting the flash off camera. Radio doesn't require a direct optical path and can be used through walls etc. The Hahnel system will even act as a remote release for the camera and controls the autofocus, drive mode and shutter release. It is dependent on exactly which model camera you've got but if it's an Olympus 4/3 SLR you should be sorted.
Ultimately, you pay your money and take your choice. If budget isn't a consideration then the 36R (or even 50R) is a good, solid, reliable flash unit which gives you basic remote wireless capability. For my money, I'd consider the Metz 44 and the Strobies or Hahnel triggers (still assuming you want/need wireless off camera). It's a more flexible system.