Well one thing to consider is that whatever you do have on your account may be rare now, so you can earn some gold that way. To get an idea of pricing you can check out the Search UO site (ignore the irl $ stuff tho) for items you think you might've had on your account (old deco and weapons/armor and even jewelry are collectables now). Or check out the rares forum here at Stratics. It won't be easy to build back up, but it will give you a chance to get used to all the changes since you've been gone so that's one good thing.
If you want to check things out before fully deciding to activate your account, you can try the 14 day free trial on a new account on the UO.com website. On another post someone mentioned a discount offer that may be happening this month, or sometime soon, for those wanting to re-open their old accounts to try the game again. So that's another option you can do for checking out the game again.
If you do decide to check out UO you'll see the new player quests and New Haven, depending on how far back you played anyhow. Magincia has also been redone and is now called New Magincia. Oh, there's also a Moongate at Britain bank now too. Those were some of the new changes to me, aside from new skills and lands and such.
Just remember nothing's written in stone
So if you pay for a month and don't like it then you can always cancel the subscription. If you don't want to tie your credit card to your account to auto renew, you can buy game time through Origin (also on the UO website) for 1, 3, or 6 month increments.
Personally, I'd suggest the 14 day trial so you at least get an idea of how things are and you don't have to pay or enter any credit card info. That's what I did to check things out in game first to see if I really wanted to play more and try to come back.
Whatever you decide tho, it's nice that you came back to say Hi