I second PK's recommendation of Solebon
. If you're a fan of solitaire card games, this is the app for you. The free version isn't bad (7 games, covers the basics), but it's definitely worth the 2 bucks to get the paid version (42 games). Regular and easy versions of Free Cell, two variations (one-card draw and three-card draw) of Klondike (the "classic" solitaire that comes with Windows), four variations of Spider Solitaire, Golf, Baker's Dozen, Monte Carlo... basically, if it exists and is somewhat popular, it's probably in here.
Honestly, I've got so many apps on my phone that I don't even use or I use rarely. Luckily, most of those are free; I only have a couple paid apps that I ended up not using.
Lately I've been getting the most use out of:
- Angry Birds -- like PK, I've got all of them except Rio (that is, the original plus Seasons and Space)
- TomTom -- I got this when it first came out. I don't have a separate GPS device, and these days there are probably cheaper options for turn-by-turn driving directions, but it works well for me. Also, this app has a car mount that doubles as an antenna for the GPS and a hands-free phone speaker.
- GasBuddy -- You said you already had this, but yeah, it's pretty good.
- Draw Something -- Another game where the paid version is worth it. Also, I really wish I had an iPad because this would be awesome on it.
- Words With Friends
- Bejeweled and Bejeweled Blitz -- Blitz is a one-minute version of Bejeweled that connects to Facebook. They used to be in the same app but Blitz was spun off by itself a few months back.
- Solebon -- Already mentioned it, but this is seriously addicting.
- What's On TV -- TV listings
- I don't use this one that much in the summer because I've got the fan going, but White Noise is good if you need some sort of noise to put you to sleep and you don't want to have music playing.
So yeah, there's a lot of games. Sue me.
I don't need it that often, but I second Sammy's recommendation of Flashlight
. I have a 3GS so I don't have a flash, but in addition to lighting up your screen, Flashlight will allow you to use the camera flash as a light.
As I was going through my inventory, I remembered I have Tiger Woods '12. It's one of the few major sports titles that translates well to mobile platforms, probably because golf doesn't require incredibly complex controls. I've had the demo versions of NHL 2K11 and NBA Jam, and they're much harder to control.
If your TV provider has an app (I think all the major ones do), get it. You can set up recordings on your DVR and most of them will let you watch live TV on your phone, though the channel selection tends to be limited. (I actually can't do that on my phone because I jailbroke it and, ummm, Time Warner doesn't like that.) WatchESPN lets you watch the two major networks, ESPNU, and ESPN3.
Let's see, what else? Most major credit card companies have their own app. If you use PayPal and/or eBay a lot, their apps will be of use to you. If you subscribe to SiriusXM and you have Internet listening enabled, there's an app for that.