"All the best" ?
A forum post isn't a letter to your best friend or a rejection letter to someone applying for a job.. You don't really need to extend a parting salutation but if you feel compelled to do so the most approriate would not be wishing US luck since YOU are the one with the problem, not us. An appropriate salutation for an OP such as yourself would be "Thanks for your responses...", whereas an appropriate salutation for a member replying to an OP would be:
"Regards,
[name]"
although for whatever reason "Cheers" seems to be popular, which brings to mind the image of someone toasting at a bar and I feel compelled to go mix myself a Bloody Mary. As you can imagine, if all the posts ended with cheers I would be seeing double after only a few posts.