Wow there are a lot of widgets out there that you can add to your blog or web page. Here is a round up of some the ones I have used so far. You can see how they will look by having a scroll round the blog.
Google ADwords. Very easy to get set up and going. Click on the Get Google ADwords box to get adding adverts to your site.
Kontactr allows visitors to my blog to contact me by email without having to leave my blog. As you can see you can use this without showing your actual email address. It has anti spam protection and was an absolute breeze to set up.
Instant messenger widgets,well there are a few out there but I opted to go with Plugoo. Plugoo works with my existing messaging software ie MSN Live Messenger which is why I went for it. Perfect for my needs but it has one disadvantage over the others in that you can only chat to one person at a time.
I got the clock from Google Gadgets. There are loads of gadgets of every type and description to choose from there.
The RSS button I picked up from feedburner.