Is it weird that I would actually consider getting an iPhone purely for that/those apps? The closest thing we get on BlackBerry is "pixtrix" which isn't as great - but I think its because of the BlackBerrys limitations.
Not overly keen on the Facebook App, I prefer just using the mobile version of the site.. the Twitter app is a must though.
Oh and on the games note.. Bubble Burst and Copter - both addictive
James