The SSD is really a great upgrade, even if you don't need it, it saves a ton of time for booting. If you end up wanting a huge amount of storage the HDD is a solid choice, but honestly, I prefer the speed on my laptop(which has very similar usage as yours)
Although I have a desktop to go with it, which gives me more storage choices elsewhere.
i dont have desktop so i will need at least 500gb for sure :/ and is there a big differnce between 4gb ram and 8gb?