Push it harder and deeper, my friend. Also make sure to ride the jeans low, that is the aesthetic.
For me, Uniqlo medium length boxer briefs. No elastic on the thigh, wide waistband, color exterior with white interior (same cloth though)
Not all boxer briefs (and/or "trunks" depending on the terminology each brand uses - I'm referring to shorter-legged ones, usually known as trunks) are created equal. I like the ones from Uniqlo - very comfortable and don't tend to ride up. More accessible for people who don't live in or travel to NYC are Calvin Klein. They make a wide variety of products though, so you have to choose carefully or experiment because not all are that great. The good Calvin Klein ones, though, are great - very comfortable and again, don't ride up. Muji ones are good too (you don't have to travel to HK or elsewhere in Asia to get them... I first shopped at Muji in Bangkok, but they have three stores in NYC now and a US online store).
I like the colors and patterns that the Nordstrom brand (in "the rail" section) sometimes has, and they're relatively inexpensive, but they fit too tightly and ride up, so not recommended. Urban Outfitters always has cool patterns and you can get them for $5 in the clearance section (and there are almost always some trunks in the clearance section), but while similar in appearance the quality is not as good as Uniqlo and they're not as comfortable (though not bad) and they're more prone to riding up.
I've tried "luxury" brands but I generally don't think they're worth it for underwear. I don't believe in just getting whatever's cheapest either, though. Not sure why some people don't take their underwear seriously, especially on a site like this. I don't like boxers because they're too loose (and easily ride up) and I don't like briefs because they're uncomfortable and I don't like standard boxer briefs because they go too far down the leg and ride up. So trunks (boxer briefs with shorter legs) are the way to go.
People, you do know that most men's underwear, whatever its brand and price point, is pretty much made in the same set of ever-shifting low wage factories? Sure, if you are going to have your silk smalls measured and hand-made by Italian virgins, you might get something different. But otherwise, uniqlo, muji, edwin, calvin klein, jockey - just get whatever happens to fit you (and this is completely ungeneralisable because we all have very different sized and shaped buttocks, thighs etc.). I know what fits me, and what I am used to, and I stick with it. There's no real point in recommending this brand or that to anyone else!