I've found Tripod to be pretty reliable, until they downsized to 20mb. They offer a choice of ugly banners or annoying popups. It's hard to beat that and still get reliability.

Angelfire seems to be pretty much the same as Tripod.

I now run my Invisionboard at http://www.coolfreepages.com/ which gives 50mb & PHP4 and has worked well for me so far. It has big popups though.