the Ultimate KML tool?

I was serching around this evening (using the spanky GIS data search engine I created using Google coop tool) and noticed an interesting Google ad that got my attention. It read “The ultimate KML Tool” (I was searching for “kml” related information. The ultimate kml tool it was referingn too was Manifold.net. The selling point the ad is making is that you can create custom google Earth layers and why pay more for less… interesting ad and i must admit I didn’t realize that Manifold.net writes out to KML. What’s your ultimate KML tool??