That's something to think about. I definitely don't want the domain name for my site to seem spammy or like some 2nd-rate knock-off of the big dogs. Thanks for pointing that out.
As a rule of thumb,you should buy .com whenever possible. Note that not all extensions fit every kind of website. For example iphonegagdets.org just doesn't sound right... .Net is always a great alternative...Besides that,there are hundreds more things to consider when buying a domain name..(domain name length,relevance to your site's content etc...)