From years of doing this I can tell you that, unless you're planning on upgrading it within the first year of having it, there's NOTHING you can do to future-proof yourself against technology changes.
In 18 months everything will be new again, and by the time you want to upgrade the system (probably much longer than 18 months from now) the parts you need will either be not-available anymore, hard to get, and/or will started to have gone back up in cost due to rarity.
Just buy the newest technologies available as it should carry support/availability for the longest time from 'now'.
Since you listed socket types as you barometer for newest technology, then you can check out Wikipedia's entry for Intel Sockets, and they list them all in a chart, in chronological order.
HTH.