Blog Site
 

If i create Blog sub domain of my website. Then chances will improve to get back link or not...

Basically blog site provided best backlink for your site .
1.http://www.blogger.com/
2. http://wordpress.com/
3. http://www.indyarocks.com/
4. http://www.tigweb.org/
5. http://blog.com/
6. http://www.allvoices.com
7. http://www.itsworthsaying.com/

The blog is very useful for improving site ranking...it will give backlinks.

but uf cose it is.
Try also for guest post for making more Back links

If you create sub domains(blog.subdomain) for your blog the link will be considered as back link, else if you create like folder subbomain.com/blog/ the links from blog will be considered as internal links.

yes sure it helps to improve your website backlinks, but you will have to keep posting new content on your blog to improve your blog then it will give benefit to your website.

The blog is very valuable for improving website ranking.
blog.com
livejournal.com/
newsleader.com/
weebly.com/
tumblr.com/
posterous.com/
blogger.com/

some most important sites of bog:
livejournal.com/
tumblr.com/
blogger.com/
posterous.com

thanks for telling these blog sites ....