It is never illegal to own a domain... it is your actions on how you use the domain which may make it illegal.
As far as TMs are concerned, typos have been considered a form of cybersquatting. If you offer products or services similar to google, chances are great you would lose the domain in a fight. When a TM holder comes after a domain, they usually say that your domain is similar or CONFUSINGLY similar to thier mark. IN this case, the domain is similar (it can be considered a typo by googel, but I believe it may also be a number, and there is also Goo Gel) but how you use it would determine if you have rights to use the domain.