Maybe wild geranium?

Looks loke a dahlia

It is a japanese anemone, they are great and spread easily.

'Anemone hupehensis' - lovely, but yes, Sarah's right, they do spread and are very difficult to remove once they have, due to their deep roots!

I have just bought one of those!!!! Woweeee, im really excited now, Its really pretty and seems to give the effect of having one pale purple petal and one deep, then one pale then one deep, its lovely,
Thanks everybody!
Lynne x

look's like a delhia to me also

Sorry, Buckeyelilly - have to disagree with you and Chris - absolutely definitely a Japanese Anemone! Look at the round buds at the end of the thin stems.

japenese anemone , a very beautiful plant , a bit invasive but you can dig out the bit's you don't want , and keep it to a manageable size.

What kind of soil and position will it enjoy the most?

If you look closely at my photos you should just be able to make out this plant in amongst the plants I bought when I bought my pots. I think its gorgeous.
Lynne x

Mine are going crazy in my wide border which faces East so they get most light in the mornings. I think they'd grow just as well in full sun - I just looked them up in my RHS book and it says 'full sun or partial shade'.