Well....that the million dollar question....but the answer is up to you. If you are planing to get into photography as a "serious" hobby I will choose no dubt the Oly 450, it is a nice entry DSLR, very compact for a DSLR, good quality, and have the advantage over the other two that being a SLR you can buy in the near future different lenses to suit you needs. If you want an "all around" type of thing and don´t want to carry lenses I will choose the Lumix its a high-end point an shoot with a nice Leica Glass in front and a very decent zoom range.
The G-11 is the smaller of the 3 I thinkm and the small brother the G-10 is well know of delivering quality pics, but it lacks the zoom range of the Lumix.

I have an Oly E-420 and it makes me happy, delivers great images, is small a lightweight and has a more Pro feel than a point a shoot, broad range of features.
Something nice about this Evolts are the lenses, Zuiko brand, most of them are very cheap and light, and the quality is very very good considering the price. HTH