I am not quite sure about the 500mb of the storage, though.
Huh? I don't understand what you mean by this.
What would be the most practical size of the storage at this point in time for a laptop?
It depends on how much space you think you'll use. Economically your best bet is half a terabyte and as you mentioned it would be enough so there isn't a reason not to get it.
If you really want to stay below $1k I'd recommend trying to find a laptop that comes with a cheap 500GB-1TB 5400 RPM drive installed then replace it with a Samsung 850 EVO
. You could throw the spare into an enclosure for $10-20 bucks and have extra space that way as trents mentioned with an external USB drive.
You could achieve this with models like these: HP Pavilion 15.6" Flagship Laptop, 6th Gen Skylake Intel i7-6700HQ Quad-Core
You'd have to watch the market though - These are the remnants of DDR3 laptops - The memory might be a tad slower, but you should be able to find them on sale for $550-700. Then it should cost you no more than $200 for the SSD, 8GB of DDR3 to expand the memory to 16GB, and a cheap enclosure for the spare drive you'd have.
If you're going to do this make sure to look SPECIFICALLY for 6th Gen Skylake Intel i7-6700HQ Quad-Core
and 8GB DDR3L 1600MHz SDRAM(1 DIMM)
. 1 DIMM being key here so you know you'll have a slot free to upgrade. When purchasing the extra stick make sure buy one that is compatible with what comes with the laptop. Some of these DDR3 laptops use "DDR3L" which runs at 1.35v instead of 1.5v - so if you buy the normal stuff it will give you an incompatibility warning if it only uses low voltage DDR3 memory.
The laptop trents listed is a fantastic deal considering it is a gaming laptop so you get the video processing power on top of everything else. Not to mention a 256GB SSD w/ 2TB addition - that thing is a steal. It's only 5.3 lbs which is more than manageable IMO. Plus everything else I've seen is roughly around 5 pounds anyways. I don't think you can get any lower than that without spending a considerable more amount of money.