A password is required for the admin account, you could just use a very simple password. After you create your standard account, when you do something that requires admin status, you will have to type in the admin passowrd (so for ease you could pick a short password - my password is one character).
On Vista, using the limited / standard account is much easier than with XP for me. You will be typing in the admin password frequently at times, but as time goes by you will type it less and less.
You will be required to type in the admin password when you make changes that effect the entire computer/ system, such as installing programs or turning off the firewall etc, many of the same things that a virus will want to do when infected. If you visit a website and it asks for admin privilidges then you know something is wrong and you won't give it the password. A website visit should not require admin privilidges unless you are trying to install software or unless it is trying to install a virus etc.
If you also use the software restriction policy (SRP) that is also described on the site, I think you will almost eliminate all chances of having a virus deliver its payload, but it also make installing programs hectic at times. Once you computer is setup as you like experiment with it.
I wish i could describe the advantages of using the advice given on the website as eloquently as needed. Just give it a good read over and try to follow all of its advice such as the standard accounts, using secunia (excellent program for keeping all programs on computer updated and patched), SRP etc).
It seems as though no one talks about using the Standard accounts as a security precaution, but it is one of the best things a person could do to secure their computer. Mechbgon describes it well.
One other bit of advice, I would go into IE7 --tools---internet options--advanced --- block third party cookies (this will eliminate most of the tracking cookies encountered on the web)