If solely as a hobby, jumping straight into Objective-C is fine, if you're talented enough to pick it up. You can always go back and learn more C later, if you're interested. But there's no clear-cut answer that works for everyone, since we're all different.If I am solely doing this as a hobby, not trying to be a top app store coder, then would it be best me learning C first or just going straight to obj-c ?
If you're new to programming as a whole I'd say learning some basic C is the best place to start. I personally belive procedural programming (like in regular C) is easier to wrap your head around when you're a complete beginner...