As a web designer, I would advise everyone to avoid Internet Explorer, although latest versions are not as bad apparently. Designers have to jump through all kinds of hoops just to make their websites work right in IE, so many don't bother and IE users suffer.
Personally I prefer Opera, it is the fastest and I'm used to it. It crashes for no reason about once a month but you can retrieve all the tabs you had open so it's no big problem. Most web designers, however, swear by Firefox.
Another thing about font sizes is that if not designed right the fonts will not resize no matter what you do. If you could post the url, I could see if that is the case with the site you mentioned.
Personally I prefer Opera, it is the fastest and I'm used to it. It crashes for no reason about once a month but you can retrieve all the tabs you had open so it's no big problem. Most web designers, however, swear by Firefox.
Another thing about font sizes is that if not designed right the fonts will not resize no matter what you do. If you could post the url, I could see if that is the case with the site you mentioned.