In my opinion, .net or .org are the best after .com. The only exception to this is if your website or blog is focusing on a specific region or country. I would use .co.uk for the UK, .fr for France and so on. If your site/blog focuses globally or on the USA then go with .com followed by .net/.org. I would also personally avoid .info or .biz domains.
I have always used .net if .com is taken. Usually for performing SEO on the .net it yields the same result as .com At least its true for me..
You can try .net and .org if .com has already been taken. Though its a proven fact that .com domains usually yield better SEO benefits, you can change the domain name you are looking for to find the match in .com list. Moreover, if you are operating under a local business, you might also want to have a look at country code top level domains like .us, .uk, etc.