I write this comment from the Black Hole, and I can't agree more that this place has finally filled the void left by Cafe Artiste's closure.
Best Free Wi-Fi Spot Houston 2011 - Black Hole Cafe
This little Montrose coffeehouse serves beer and wine, but what makes it a great place to do a little after-hours work or telecommuting is the spacious dining room — more so than its Heights cousin Antidote — and free wi-fi. You'll see plenty of students here pecking away on their laptops or updating their Facebook pages. Their laundry is probably spinning away in the washateria next door.