While I enjoy playing Guild Wars with a group of friends -- since it is a multiplayer game -- I definately love the challenge of playing solo. Specifically, soloing at high-levels without support of heroes or henchmen.
The PvXWiki has a number of great solo builds. These builds are often labeled as "farming" builds, but I don't think they really exploit anything. If you're willing to risk your life going up against dozens of mobs simultaneously, and survive, you deserve a little better reward. I personally don't think the rewards are that much higher in most circumstances than the rewards from designed solo encounters like Kilroy Stonekin's Punch-Out Extravaganza in hard mode. Depending on luck, probably equal to. But you get a lot of variety if you bounce around, and that's what I like.
I've been into the Vengeful was Khanei builds lately, specifically one to solo the first wave of Glint's Challenge. I've used a similar build in the past to collect Dead Swords and other rare weapons by soloing the Destroy the Ungrateful Slaves quest. But verses Destroyers, you have to be extra careful.
This is the build I've been using: W/Rt Solo Destroyer Core. Definately not my own work, I borrowed the build and idea from the PvXWiki. It definately works as advertised. In a single run that takes about 5 minutes I've gotten five destroyer cores. If you're trying to get 250 for Destroyer Gauntlets, it won't take you too long going this route. Plus it's just fun to survive getting beat down by 50+ Destroyers.
And that's really the point, right?