Hi Richard,
I'm glad if in a small way I've inspired you to look at legacy lenses
You may know that you can fit lots of different lenses to Micro Four Thirds cameras as long as you have the right adapter and of course it helps if the lenses have an aperture ring too but assuming that you have an aperture ring and the right adapter you should be good to go for relatively little cash
Popular legacy lenses for use on MFT seem to include Minolta MD/MC, Olympus OM, M42 and Canon FD and doubtless there are many more out there too plus of course there are numerous companies that made Olympus and Minolta etc fit lenses.
With a little bit of research I'm sure you'll soon be well informed and you can always ask questions here too.
I bought lenses from the classifieds here, from ebay and from used dealers like Ffordes. Here's a link to Ffordes where you can have a look at the used Canon FD, Olympus OM and Minolta MC/MD lenses. They also stock adapters but personally I just bought cheap ones off ebay. Ffordes adapters seem to start at £20 but I think I paid about £10 on ebay. Anyway, here's the link to Ffords but of course other used kit dealers are available...
http://www.ffordes.com/category/Photo_Accessories/Lens_Mount_Adaptors
These people sell adapters too...
http://www.speedgraphic.co.uk/other_accessories/body_adaptors/140_0c.html
Here's some cheap ebay ones...
http://www.ebay.co.uk/itm/Minolta-M...ns_caps_hoods_adaptors_ET&hash=item232194dec1
http://www.ebay.co.uk/itm/Olympus-O...ns_caps_hoods_adaptors_ET&hash=item19ba835af1
What you want is a lens to MFT adapter so it'll be described as (lens to body) for example... Minolta MD to MFT, and of course you want it to support infinity focus.
28mm f2.8, 50mm f1.4/1.7 and 1.8 and 135mm f3.5 lenses seem to be relatively easy to get plus there seem to be plenty of 50mm macro lenses about too.
That picture I posted earlier is a Minolta Rokkor lens fitted with the lens hood from my Voigtlander 25mm. Here's a picture of my G1 fitted with a Rokkor 28mm f2.8 via a Minolta MC to MFT adapter.
It's wearing a metal lens hood I bought for very little money off ebay where you can also pick up lens caps. I like these metal lens hoods. They're available for as little as under £2 but note that if you want to leave them on your camera you may want to buy a lens cap to go on the end. For example the 28mm f2.8 in that picture would normally take a 49mm lens cap but with the hood fitted it takes a 52mm cap.
I really like using these old lenses. With their aperture rings and mechanical focus mechanisms they're a joy to use. You can zone focus or focus at infinity very easily and with the cameras magnified view focusing isn't a problem.
Just because I can

here's some legacy lens shots I like, all 28 or 55mm. They'll be mangled a little by Photobucket but they're all sharp on my screen

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