Recommended M42 screw mount lens

Hi,

I picked up a Takumar 55mm f1.8 a couple of days ago along with an M42-m43 adapter. I'm really impressed with it. It's my first legacy lens for the GF1 and I've had loads of fun so far (quick picture below). It was also a nice bargain from a local collectors. I've definitely got the legacy bug. Are there any other notable lenses in M42 screw mount I should be keeping my eye out for? The 50mm 1.4 has got to be one but can be pricey on ebay here (uk).

If you have any experience with them and can offer some suggestions I would greatly appreciate it.

Thanks,

Danny

http://www.pixelnoise.co.uk