As a general rule, players of MMORPG's like (a) unique appearances for their characters and possessions, such as houses, plots and lairs, to distinguish them from other players' characters, and (b) to be rewarded, indeed recognized, for their longevity in the game.
I would therefore recommend that the developers implement a reward program for players based upon the age of their accounts. The rewards, in my view, should not affect game balance (e.g., the holder of say, a three-year-old account would not receive the "Sword of Uberness" with +500 to two-handed slash), but would instead be marks of distinctiveness to the character of the player's choice.
The type of rewards would be limited solely by the developers' creativity and coding limitations, but here are a few examples of such rewards:
1) Placeable plot decorations, such as statues, flowers, rose bushes and the like. These decorations would not be buildable, per se, but would appear in a biped character's backpack and simply be placeable somewhere on the character's plot. They would also be freely tradeable/sellable.
2) Placeable lair decorations, such as murals, dungeon-related items such as hanging skeletons, and the like, with the same features as plot decorations described above.
3) Hoardable items with increasing values per age of the account (e.g., a 100,000 hoard value item for a one-year-old account, a 250,000 hoard value item for a second year account, etc.).
4) Unique clothing/armor/scale that either (or both) (a) possesses colors not available in game via dye kits, and/or (b) grants some small increases to a stat or skill not otherwise available in game (e.g., a platemail chest piece that adds +30 to ethereal armor).
5) A one-shot ability to change a character's hair style or color, or for dragons, to change or at least tweak the colors and highlights of his scales, perhaps in colors not available in the character creation menu.
6) Progressive titles based upon age of account. For example, a character on a one year old account would have "Sir" or "Madame" added before their names, "Baron/Baroness" for second year accounts, and so on.