There are loads of new threats waiting to pounce as you surf the WWW and we are seeing them getting very sophisticated (As in they’ve learned to use a spell checker). The biggest security hole in your PC is the software you just don’t notice or the update dialogue annoys (Flash, Java, Shockwave) so you cancel it (Sound familier?).
Here is a little file that when run will check for updates of various oft ignored software and update them for you, its easy just download it and run it – and yes it is safe. I would suggest running it weekly to be on the safe side and if you want to have a go at building your own (Easy) checkout http://www.ninite.com. Get the file here.