Bought into the m43 system with the gf1 when it was first launched and it kick started my interest in photography again (had a canon 300d previously but the then girlfriend/ wife now complained about the size and how conspicuous it was and after a while, I got lazy carrying the camera.) Now I'm back with a vengeance!
Recently returned from Antarctica and I brought 3 camera bodies (2x gf1, 1x GH2), 9 lenses (mix of zooms & primes covering range of 7mm to 300mm) and accompanying chargers +3 spare batteries. All this fit into a Kata haversack (plus my trusty MacBook pro with an extra 2.5 inch hard disk). I don't think I would have been able to carry that wide a range of gear in such a small haversack had I been carrying a regular Dslr system. (why 3 bodies? To reduce having to change lens and given it was a 20 day trip with no camera shop to buy a replacement in the event of an accident/ failure, I would still have something to shoot with!) - I also packed an oly xz1 with underwater housing but in a different bag. All my equipment survived the trip well (the snow, cold weather ice and sea). On a trip like this, multiple redundancy is very important. There were so many ruined cameras on the trip- I'm talking wrecked weather sealed slrs from sea water spray, snow and people falling overboard (ok, nobody fell overboard but a few did stumble during the wet landings and ended up with their cameras in the water)- another big plus for the m4/3 gear is they are so small and fit easily into regular sized zip lock bags for waterproofing for such eventualities!
Just bought a gx1x today. feeling really really guilty about it because I was telling myself not to buy the camera since I don't really need it since i still have my first gf1 and the gh2 (and i still have to get around to spelling the spare gf1 i bought for the trip). But it was so tempting... I was walking by CP in Marina doing other xmas shopping and went in to take a look... They had the beautiful gx1x on the shelf so I went in to try it... ( i was more interested in the x lens- that I honestly gave myself permission to buy if they had the lens only but no they did not have that option). Long story short, ended up buying the camera (supposedly the last piece) and got "the look" from the wife when I came home today.
Anyway, my kit tally:
1) pana gf1 -my first true love in photography. That's right, sorry to my old "ex", the canon 300d but you never inspired me the way the gf1 did. By right I should sell the gf1 now but for sentimental reasons i'll still keep it in my dry cabinet. It's faithful partner being the lvf1. Both having served me well for 2 years+
2) pana gh2. - my second love in photography.
3) pana gx1- verdict is still out there... Still feeling guilty regarding the splurge (1 night stand?

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4) pana 7-14mm
5) pana 14-45mm (from gf1 kit)- rightfully should go since I just got the 14-42x...
6) pana 14-140mm- rightfully should go now too after the trip...
7) pana 100-300mm
8) pana 14mm
9) pana 20mm (from gf1 kit)
10) pana Leica 25mm
11) pana Leica 45mm macro
12) oly 45mm
13) oly 14-54 mk2 with mmf2
14) pana 14-42x