Domain name turn offs?

It doesn't matter squat.

Thanks so just go for the cheapest?

I think these days it really doesn't matter, in the early days people used to think of one as "more reputable" than the other, but now it is just whatever tickles your fancy.

Actually, com is best. Most often thought of, and the FIRST DEFAULT!
.net is a close second, often thought o, and second default
.org is next best, third default.

.info is a JOKE!
.co is not often considered in the US, and may be a typo of com.
.us is not often thought of even in the US!!

but official and reputable? You have been watching too many state farm commercials!

Steve

It depends on the nature of the business.

Marketers quite often don't like ".info". Customers - other than in IM and MMO niches - typically do: they think it speaks of an "informational" sort of site rather than "just another person trying to sell stuff". In terms of customer perception, that's very signficant.

(".us" is available only to US residents and those with a genuine business presence in America, not to other nationals. I certainly wouldn't want to use that other than for a US-only niche, and even then I'm not sure).

I nearly always buy the .com extension for all my domains (even though I often don't use them), just because I don't want anyone else buying them. I use ".info" from choice, in every one of my niches, because my customers, visitors and subscribers prefer that (and say so, loudly and clearly and in large numbers, whenever asked, and many even even explain why). I just redirect the .com domain I'm not using to the .info domain I am using, each time. Still, I admit I'd be pretty uneasy about building part of my business on a domain-name of which the .com version actually belonged to someone else - partly because of the potential for losing type-in traffic, but for some other reasons, too.

For all Google SEO/ranking purposes, all the top-level domains are exactly the same. There are actually a few hundred threads on this very point, in this forum (some in the Main Marketing Forum and others in the SEO Forum), some of them containing links to Google-owned websites and videos in which that's expressly and repeatedly clarified by Google. But in spite of all that, there are also still a few (perhaps very few, now) people who simply don't believe that. (What incentive or motive they imagine Google might have to lie about it so repeatedly I can't begin to imagine.)

What type of business you need the domain name for? If you want to start eCommerce site then .com would probably be the best option or for hosting service .net would go quite nicely. For informational sites and info products .info would be a very good choice. But I think that now the original intention for the domain extension are long forgotten. But whatever you think is most suitable for your business, like Alexa said, try to get the 4 main extensions under your control which can be quite difficult to do with a short domain with popular keyword. Usually the domain names I like 15 or more extension are already taken so you really need to be creative nowadays.

Depends on what the site is for. If it's going to be an authority type site, I'd go for .org or .co. I've had a lot of .info sites that did well. The only domain extension I never use and don't like at all in the above list is .us.