Black Knight Irios
Explorer
Any suggestions involving the warlock's use of weapons isn't cool, because the most interesting things going for warlocks are the tactical combinations opened by double rods.
I was partial to using a Rod of Reaving as my implement with a +1 Rod of Corruption in my off-hand; the Rod of Corruption's effects don't scale with enhancement, so there's no need to replace it, and between the two you can wipe out pretty much all the minions in an encounter as a free action. (Curse one, it takes damage equal to enhancement bonus from the Rod of Reaving, it dies, you sacrifice the pact boon to instead curse everybody within 5 squares... and they all immediately take damage equal to your Rod of Reaving's enhancement bonus...)
You know it is nice to mention this but you have to consider the following: You can't have everything with every build!
Sometimes you have to sacifice options for a higher success in surviving encounters.
Decide what you want but don't blame the game that you have to make choices that are meaningful.