Haven't played in a while...

The last upgrade I bought is Nightfall. Is EotN worth buying? What does everyone think of the upcoming GW2?

Buy Eotn if you plan on buying GW2, as you can save some achievements and armors for GW2, otherwise, just a reskin of older releases.

So is EotN required to save achievements when upgrading to GW2?

Yup.

from wiki:

The Hall of Monuments is an explorable area in the Eye of the North expansion and will be incorporated in Guild Wars 2 to help tie the games together and reward dedicated Guild Wars players in Guild Wars 2. Certain achievements will add monuments, and each monument will unlock something, such as an exclusive item or title, for a character on a linked Guild Wars 2 account.
Note: Having something in your Hall of Monuments does not guarantee that you will get that item when Guild Wars 2 releases; ArenaNet has stated that you will get something, but it may not be the exact item.

Here is the link, read it:
http://guildwars.wikia.com/wiki/Hall_of_monuments

Thanks a lot. I guess I will be buying EotN then.

If you like Guild Wars Lore, and of course... GW 2, you HAVE to buy EotN.

It's the best campaign after Prophecies in my opinion and it has lots of fun to explore and to do.

I haven't played it yet, but it does sound really cool. GW2 sounds amazing. I know I need a new computer for it though.

Nightfall wasn't an upgrade.

We aren't talking about GW2 because we know nothing about it.