Guides by Modern Luxury: Modern Luxury goes where lesser apps fear (or can't afford) to tread. Typical city guides list boutiques; ModLux has plastic surgeons. Ordinary iPhone apps offer mere words, but ModLux has slick custom video. And while basic video has a beginning and an end, this one has a bonus surprise: perks. Reach the end of a video clip—say, from Intermix—and get a special deal there and then. Hotness in motion. —Foster Kamer

Tumblr: Finally, mobile access to the microblogging platform that’s taken artists (director Rian Johnson), musicians (Lenny Kravitz, Ra Ra Riot and BlackBook staff writer Ryan Adams) and writers (too many to count, including us) by storm. The Dashboard—where new posts appear—is streamlined and beautiful. Record voice memos or upload images (or slideshows!) directly onto your blog. Plus, with the iPhone’s new cut-and-paste feature in full effect, bloggers can publish incriminating emails in no time. —F.K.

iFitness: Cut out the angst and stress of a real personal trainer by packing one in your pocket. With how-to images of workout routines and exercises that target specific problem areas, along with the option to compile a full workout and keep tabs on how much fat is being burned, users need never feel inadequate again. —Eiseley Tauginas  Instapaper Pro: Never again suffer through long flights without cellphone service, cut off from the Internet. Instapaper Pro lets readers select and download articles and webpages, while they still have bars. Plus, “starring” an article makes it available to subscribers on their “Starred List.” New folders encourage organizing and subscribing to websites with feed folders—any excuse for being out of the loop just disappeared. —E.T.

Drinktracker : DUIs sure do get in the way of a good time. Fortunately DrinkTracker now minimizes (or at least quantifies) the risk of getting behind the wheel while still a little loopy. The app calculates imbibers’ BAC—the level that, when tested by a breathalyzer, determines whether or not you’ll be spending the next few months doing community service. Users plug in weight, height and the drinks they’ve downed, and then find out their likely level of intoxication. Also neat: a timer helps count down the time until it’s safe to drive again. —Foster Kamer

Craigsphone: This app takes “local” to the next level, allowing users to post to the infamous online classifieds at Craigslist.org, call directly from their phone, upload photos, view their history and even see relevant Craigslist entries. Whether it’s a ticket to a sold-out show or Nintendo sex with anonymous shoe-fetishizing closet transgenders, Craigsphone finds it faster, easier and closer. —Alexandra Vickers

Currency Exchange Rates: One problem with navigating foreign lands is getting consistently screwed on the exchange rate. This app uses the iPhone’s new and improved push technology to keep tourists up to speed on the latest rates. Finding an exchange is still a hassle, but at least now travelers can shove their phones in the face of the Travelexx clerk trying to buy their five dollars for one pound and let him know that, hey, man, it’s actually worth one and a half. Sigh. —F.K.

Colorsplash: This is the best iPhone camera utility, period. Spy an object—say, a particularly orange flower or a beautiful vintage sky-blue Vespa—take a picture and Colorsplash will suck all of the color out of everything but the object you’ve focused in on, leaving the rest in black and white. Take stunning photos and leave the digicam on the shelf; this one’s got all the necessary tricks. —F.K.