I'm really surprised Olympus hasn't offered a model with a built in EVF.
First day I used my GF1 in full sun I ordered the LVF1. Resolution kinda sucks, but it gets the job done at minimal cost. Bit of a pain to have to bring it along, though and mount it and dismount it and when it's on the camera the nice form factor is killed.
Better yet... the G3! Small size, somewhat sleek form factor, built in EVF, fully articulating screen, great IQ, relatively low noise at higher ISOs, there's a LOT to like about this and I think Oly is missing out big time on this market.
Speaking about the LX5 - wow, I love my LX5 and would not want to give it up... I use it all the time when I want small and convenient for casual grab shots.
I have used the LVF1 on my LX5, but typically just shoot it with LCD. The accessory I use quite a lot on my LX5 is the Wide Angle lens - I love that on the LX5 - even though I have the 7-14 form my GF1 and GH2. There is something I really like about the LX5 with the WA lens. I could just as easily grab the GF1 with the 7-14, but then I'd need to bring another lens along for longer lens needs. I'm surprised at how much I use my LX5 and how much I love it. It creates awesome images for a relatively small camera. I got the WA lens because I find myself often at the widest (24mm) setting on the LX5 and wishing for a bit more field of view... the WA takes it to around 16mm or so, if I recall correctly, and you can zoom the lens while the WA lens is attached, which is great.
I would also love an LX5 with a built in EVF and wouldn't mind a slight bump in form factor to gain that - it would be a killer camera! Of it the XZ-1 focal length came down to 24mm and included a built in EVF, that would be ok too.