Congratulations on getting to 2,000,000 BIS miles, that is a lot of time in the air.
When I hit the 2,000,000 mark I selected a nice suitcase as my gift. On one flight I was having trouble fitting it in the overhead. The flight attendant told me I would have to check it because it was too large. I told her that didn't make sense since the bag was given to me by Delta. She asked if it was because they had lost a bag before. I told her no, I received it for reaching 2,000,000 miles. She smiled and said she would make it fit.
On another note, when I hit 2,000,000 Gold Medallion was the middle tier and had some real advantages. When Delta added the Diamond level that never made any adjustments for 2,000,000 / Complimentary Annual Gold Medallion holders and let the primary benefit devalue. Really bad form Delta!!!