[xdude]

If you plan on heavy use then go for a flagship version. Samsung Galaxy S series is a great work horse. But You don't have to go for the latest model. just go for a few models back. You will get it cheaper and you will find it's specifications are lot better than latest economy level models. That's even if your flagship model is several years older! Goto gsmarena.com and compare each promising model for your budget range. Check things like RAM, Processor, Internal storage, Screen size, Battery etc.

If you want good photos then go for an Older model of Apple than Samsung. When it comes to camera I have to admit Apple has better quality.