The ending of the letter

[Gość: Kamila..]

Hello all. What endings of letters, e-mails do you know?
For instance:
best wishes,
greetings,
talk to you soon
love (can we use it when writing only to a boyfriend/girlfriend or also to
good friends?)

[Gość: Bodzu]

You want informal, don't you ?

eg. :
See you!
Bye!
Cheers!