Am using Aussie mega which is supposed to avoid build up. My hair is shoulder length, medium to fine texture, and straight. I wash it every 3rd or 4th day. After I blow dry it, it looks good but even by the next day I feel it's looking a bit 'lank' at the back and it feels as if it has product in even though I've rinsed like mad. I've tried expensive stuff like Aveda but didn't notice much difference.
I've been loving Ojon conditioner for about a year now - expensive but it works really well for me and seems to wash out well with the minimum of effort. Also, a little goes a long way so one bottle lasts me ages. I've got short thick wavy hair that tends to frizz though, so nothing like yours.
Aussie range is absolutely disastrous for my hair, don''t know why but just doesn't agree with me!