JANDD MINI MOUNTAIN PANNIERS
These were the first bags I ever bought specifically for a bike commute, and I've become a big fan of all things Jandd based on the 10 years they have now lived on at least one of my bikes. The materials and construction are about as tough as a Paris-Roubaix rider's backside, and when the hardware is properly adjusted, they lock to the rack with absolutely zero sway. The expanders can take them from fairly sleek to touring-kit devouring (in fact, I've done a three-day tour with just these bags and a couple things strapped on my rack). Downsides? They are very water-resistant, but the zippers and hardware holes make them just short of waterproof. Like most panniers, they're a bit awkward to carry off the bike -- two (snapped together with the thick leather handle) are wide and bulky, while one leaves poky mounting hardware exposed (including the stainless hooks that can scratch up rack rails in use). And, that mounting hardware is definitely designed for extended tours rather than day-to-day utility cycling. It takes some finagling to get the bags on and off the bike (a minor nuisance that becomes a major annoyance when you do it twice a day in heavy gloves), and they don't always swap nicely from one rack to another without a fairly involved hardware re-adjustment. But, if you're a one-bike commuter who values toughness and stability over quick-release convenience, they'll likely outlast whatever bike you put them on.
TIMBUK2 MESSENGER BAG (MEDIUM)
I confess, I'm such a bag hound, I'm now on my second medium T2 messenger. The first was my "I'm a grown-up with a real job, time to reward myself" gift when we moved to Des Moines, a custom in no-longer-available waxed cotton canvas. For whatever reason, I temporarily lost my taste for M-bags shortly after, never quite liking the way it hung on my back, and ended up selling it. Duh. So several years later, there I was replacing it with the same thing in non-custom Cordura. I know that the T2 messenger is so fixie-hipster ubiquitous these days that it's a cliche to even sling one on, but I'm also convinced there's a good reason for the popularity beyond just hype. The waterproof liner actually works, the bag stays (mostly) where it belongs on your back when the straps are properly adjusted, and you really can spin it around to grab something out of it like a real messenger on a double-rush. The medium size has been the "just right" for me -- I can't fill a large with my commute gear, so it flops around half-empty and twice as uncomfortable. You're still going to get Sweaty Back Syndrome from it (especially if you sweat like I do), but that's pretty unavoidable with a bag you wear. More-hardarse-than-I guys report that these won't hold up to "real" messengering, but I certainly haven't been able to wear mine out in "civilian" duty. If I have to carry a laptop, this is what I use.
ARKEL UTILITY BASKET PANNIER
I bought this as a reaction to my Jandd Mini-Mountains, hoping to find a "perfect" pannier to address their quibbly shortcomings. Of course, looking at the Arkel site, it seems like they've redesigned this bag a couple times since I got mine, so the bag you buy today won't look at all like my construction-orange "vintage" one. What I like about the UB is that it's just one giant bag with a couple little pockets here and there. It's actually designed as an uber-fancy grocery-bag pannier, but for my needs, it's an ideal commuting pannier. You just dump your stuff in, lock it on the rack, and get gone. The Arkel mounting hardware is quicker on/off, more thick-glove-friendly, and easier to adjust than the Jandds -- and that's the first generation. The latest iteration is (reportedly) even easier to use, incorporating a "pull the handle to release" feature. Like just about any pannier, the UB is awkward off the bike, kind of unbalanced and poky. The flat bottom is nice when you reach your destination, though -- it sits up for unloading rather than toppling over. So, whenever I need to carry more stuff than I really should, I reach for Big Orange.
REI FLASH 18 BACKPACK
This was kind of a fluke impulse purchase, because, well, I'm a bag fiend. I tried REI's bike-specific Novara commuter backpack and loathed it... too heavy, too uncomfortable, and just way over-designed for anything short of "expedition commuting" (for example, if your office is on the summit of K2). So I returned it, but on my way out of the store, I noticed this little yellow backpack that seemed like everything the commuter wasn't: lightweight, close-fitting, simple, compressible, comfy, and relatively cheap. It's basically a big hydration pack without the bladder (though it has a pocket and hose access point if you want to add one). The minimalist straps keep the load right where it needs to be, and the bag itself adds almost no weight to my commuting kit. Like any backpack, it will cause Sweaty Back Syndrome, but the small footprint back there (backprint?) helps a lot. Downsides? Well, it is small. My laptop won't fit, and if I need to pack a pair of shoes with my clothes/lunch, things get pretty tight. The stuff-sack-style opening pretty much sends rain an engraved invitation, too. And, since it's not designed for any sport that puts the wearer in traffic, it is sadly lacking in reflective details. Still, this bag continues to impress me the more I use it, outperforming stuff that costs twice (and thrice!) as much. Nice work, REI, and not just because I'm a card-carrying member. (Stupid fun detail: The orange buckle on the chest strap is actually a very loud whistle that both scares the snot out of motorists and does a cool blowing-across-a-bottle noise when I'm riding at terminal velocity.)
So, there you have it, and I hope that it wasn't too spammy-sounding. If there are any other bags you'd like to see reviewed, just let me know. Considering how many bike bags I've bought, tried, stashed in the garage, passed to friends, and/or resold, I'm sure whatever you're looking for will wind up in my arsenal eventually... and at least I can justify it as "for the good of the blog" if it eventually winds up here too.