New Workstation

for that money, you will probably end up with a single E5-2687w V4.

for ram, 64gb would be the starting point, but large long-form projects and high res media 6-8k might benefit from more. if you are using after effects it will likely be the most demanding for ram and you could get up to 128gb for that program. if you do go with the 64gb, as long as you order the system with 4 sticks of ram you would have the option to add more later if needed.

for video cards, if you are adding your own gtx card to save costs, you could get a cheap/basic quadro in the dell order and then replace it with a gtx 1080. if it has to be a quadro, but not from dell, you could get a quadro P5000. if it has to be from dell, they might not have the new P5000 and the old quadro m6000 or dual m5000 would be an alternative. it would be worth trying to avoid the old M series quadro's as the new P series are a good step up. one gpu will likely be plenty, but the more gpu accelerated fx/grading and any gpu based plugins or software, and gpu accelerated or red media, the more the system might benefit from dual gtx 1080 or dual P5000. premiere can use dual gpu, but not all software or plugins can. you may want to make sure to select a higher watt psu around 800-1k while ordering the dell as well, just to be covered for adding in more video cards later.