(In addition to the seven previously mentioned, here are two mediocre products that I couldn't live without...)
8. The venerable DustBuster.
The pride of '79, and for good reason. The most overlooked aspect of the DustBuster is that it is quite obviously made for... men. I mean, who else but a guy would want to vacuum up one square-foot of filth, while leaving the rest of his apartment looking like something Gazans would take pity on? On a whim, I bought this for my wife last Christmas. (I guess it was the NyQuil; normally I only recommend buying your wife a cleaning product if you miss being single.) Luckily for me, she kind of fell in love with it. This is a beaut when mom calls to say she's coming over, and an absolute must if you have children younger than, say, thirty-five.
Bonus: it looks a lot like a Picard-era phaser. (If they ever made one that looked like a TV remote, men would have tidier apartments than Felix Unger.)
9. Drop cloths
Bar none, the most boring item here, a drop cloth is something you either have or you need. But what it lacks in sex-appeal, it makes up for in utility. Drop cloths have one job: catching paint drips. And if you ever need a blanket after being kicked out of bed for buying your wife a DustBuster, you could do worse. This is a for-life purchase. Once you've vacated your crash pad at Tappa Kagga Bru, your ripped Lamborghini posters and "No Dumping" signs aren't going to cut it any more. You will need to paint walls, my friend.
Parental bonus: when my kids decided to take a stab at abstract expressionism, a couple of drop cloths placed with Dexter-like precision around the canvas saved me from a massive stroke. Heck, I use one in the living room when they eat spaghetti in front of the TV.