But now that I've gotten a few socketed pieces, they, well, suck. At 62, I got this awesome vest for my Shaman from a quest reward-- +44 spell damage and healing, 6mps, 21 stam, and 15 int. Then, at 64, when I took down Mennu the Betrayer in the Slave Pens, I got this baby-- the Vest of Living Lightning, complete with red, yellow, and blue sockets.
And after hunting around for gems a little bit, I am unimpressed. At the gem merchant in Thrallmart (yes, Thrallmart, for all your Outland needs), the best I could find was a little +9 healing and a little int and spirit-- even with those bonuses, the socketed vest doesn't match up to the quest reward. And even at my Aldor vendor, I couldn't find any gems that came close to making me switch away to the new vest. In the end, I vendored the socketed item. Likewise, the pictured item sucks even with three yellow gems in it when compared to what I'm wearing, the Scaled Legs of Rumination.
Now, I'm still in the low levels of socketing, so it's very likely that both the socketed gear and the gems will get better (I didn't check the AH at all for gems, which I probably should have). I've already seen the Tier 4 pieces, and those have amazing stats and sockets, which definitely makes them amazing. But for standard, mid-60s socketed pieces, it just doesn't seem worth it to run around looking for gems, when other non-socketed items are so much better.
Update: Apparently I should have checked the AH-- there are lots of great gems in the game if you're willing to hunt, mix, and match. I'm still not sure it's worth the time to make a lowbie socketed item better (I'll probably wait for the higher stuff), but if you want tips, check the comments.