There's no reason not to have more than one browser either

If you are using Windows, you must have Internet Explorer installed. It is the same program, with a slightly different "hook" that does all your file handling under the alias of Windows Explorer, and that handles the access to all the little "maintenance feature" in Windows. It cannot be uninstalled without "breaking" Windows.

If you have IE installed, you have all its "vulnerabilities," and some of them may be "exposed" whether you use it or not. Even if you never open it, you need to keep it up to date, preferably with autoupdate.

If you've "updated" to Vista, and if you've kept it up to date with autoupdates as you should, you should already have most of the patches and changes that are part of Vista SP1. The complete SP1 is now released, and will be installed, complete, via autoupdate, with a few exceptions. The consensus opinion of competent advisors is that most people should allow SP1 installation.

There are a few programs that are known to be "blocked" from running in Vista SP1. A short list of known programs can be found in the Microsoft Knowledge Base article 935796.

The list at the KB article is not a complete list. It includes a couple of AV programs that are blocked due to "instability" with SP1; including Bit Defender or Zone Alarm. There are compatible updates available for both of these. There are a few programs that are listed as "will not run" but none (on the list so far) that I've heard of anyone here using. Updates are available for some of these.

There are also a few conditions, including presence of non-compliant programs, that will prevent installation of SP1. The download/installation program checks for some conditions and will not download SP1 if certain ones are on the computer. If you have Vista, and SP1 doesn't appear within the next month or so, you probably should find out why and take steps to get it.

There likely will be more discussion on Vista SP1 when more people have it.

John