Q:
storyline rewards
http://wiki.guildwars2.com/wiki/Personal_Story
You can just click through that to see the rewards. Nothing special although there are a couple of pieces that are only obtainable through the personal story. Making different choices will not change the rewards so you just have to follow one branch on the wiki.
You won’t get better stats than you have, and the items rewarded won’t scale to 80. You will get a few skins you can’t otherwise get (the medium Stalwart coat, for instance), at least until they change the division between PvP and PvE skins. You’ll also get some fun story, and if you get all the way through 80 including the Arah Storymode (easy for you as you like dungeons), then you get a token — one per character completing — for a Pact weapon. The Pact weapons are tradeable, you can view them on the TP.
If all you want is useful loot, though, no, the PS isn’t the source of that.
Some of the higher level rewards have decent upgrades on them if you have a BLSK lying around.
At 80, you’ll get some skillpoints I guess.
And it takes some of the clutter away from the top-right of the screen.
You might enjoy some of the forks in the story, as well, so that could be a little reward.