Need help with purchasing external HDD..

Hey guys. I want to buy an external hard drive for my laptop. I want a 500gb one. I was looking on newegg and found these 3 cheapest between $80-$82, all with free shipping. So I am confused with which one to buy. Please help me in making a decision.

http://www.newegg.com/Product/Prod [...] 6822101122
Cavalry CAUM CAUM37500-B 500GB USB 2.0 Black External Hard Drive with OTB
Dont know the RPM or cache for this drive. No reviews. 1yr warranty.

http://www.newegg.com/Product/Prod [...] 6822136080
Western Digital Elements WDE1U5000N 500GB 7200 RPM 8MB Cache USB 2.0 External Hard Drive
Not pre-formatted. Decent Reviews. 1yr warranty

http://www.newegg.com/Product/Prod [...] 6822148235
Seagate FreeAgent Desktop ST305004FDA1E1-RK 500GB 7200 RPM USB 2.0 External Hard Drive
3-yr warranty but recent reviews are not good.


Also i found a $65 one at PriceWatch.com, Simpletech Pro Drive 500gb(3yr warranty) which has USB 2.0 and eSata interface but i am not sure of the website which is selling it. Have a look.
http://www.enetshoponline.com/siprodrusexh.html

So please help me with which one to buy or if you can tell me other better deals.

Thanks.