Here are the places I frequent most:
Letter of the Week (we use it for the sound of the week)
Hubbard's Cupboard - great Bible & general curriculum for preschoolers & kindergarteners
Ambleside Online - all sorts of Charlotte Mason curriculum and book suggestions
Freebie of the Day - cool, cool site with a free download each day. You never know what you're going to get!
This and this are good sites for making tracer pages, and here is a place to make your own word searches!
I also go to DLTK a lot when I need a simple craft or worksheet to round out a topic.
Starfall is good for reading.
There are tons of others in my favorites but these are the ones I use the most. These and Google, of course. ;)
We used to LOVE Rainforest Maths, but the website is closed now and we haven't found anything to replace it. Do you have a favorite math site?
To find your own new favorites be sure and visit all the entries at HOTM!