Thank you all for such helpful responses! This morning (before reading your replies) I decided to take the plunge and coated my hair in olive oil. I left it on, shampooed it out and conditioned. My hair is smooth and shiny today

A little trim of the bangs helped too.
Riddy - I'll have to look out for mango oil, I'll bet it smells WAY better than olive oil!
Kelly315 - I know what you mean re: dying. Something about it makes it nice and smooth, and the conditioner that comes with it is AMAZING. But, I lighten my hair a fair bit now so colouring is kinda tricky. Part of the reason I'm looking to deep condition is to keep my hair healthy post-bleaching. The things we do for beauty...
Horo - good tip re: a little goes a long way. I find a bit of product on the ends of my hair really makes a huge difference, but I don't want a greasy look.
IsobelRose - I think I'm going to try coconut oil too. Olive oil was nice, but I'd like something without the olivey smell that I can use to smooth out a few stray fly-aways and any split ends and I think coconut oil will be good for that.
JerseyGyrl - I like some other products by Organix so I'll keep an eye out for their oil. I've co-washed before but never knew it by that name! Sometimes I just want to rinse product out of my hair and smooth it, and shampoo can strip it of its oils too much.
sontaikle - I would skip shampoo, and I used to, but since going blonder I NEED to use purple shampoo to keep the brasiness at bay. Otherwise, I start to go orange and yellowy very quickly.
Brown - I'll have to keep my eye out for that brand. I know some people have issues with silicones or any -cones, but I don't know enough about them to know what's so bad. I suppose I need to read up. I have read though that silicones are supposed to be great moisturizers so I don't know if I could give that up!
Sorry for such a long reply - just felt you had all said such important things!