Backlinks are necessary for better search engine rankings of your website. It help you to promote, increase page rank and make your site valuable. However there are certain things you should take care of while creating backlinks to your site:- 1)- They must be Dofollow if you want search engines to give value to your site. 2)- PR 4+ Backlinks are best and must be from variety of sources like Forum Profiles, Social Bookmarking etc. Hope this helps.
Backlinks not only help you to increase search engine ranking but also get the top position in Google.