Funny, I was in that same store yesterday :p Indeed, the price in the store itself is still 155. I listened to the Shure SRH840, AKG K 271 MkII and the KRK KNS 8400, all of which are around the 150 pricepoint, all closed and all (fairly) neutral. I decided to go with closed ones, that way I can use them for live sound as well (I do some sound enigneer work in my free time). In the end I had a hard time deciding between the AKG's and the Shure's. I went with the AKG's, because they come with both pleather and velour pads, and two different cables, and according to the guy the warranty on them was better, Shure won't do repairs if there is a possibility you broke it on purpose. Sound-wise I found them quite comparable. I tested them unamped, straight from my iPod. The AKG's do have a slightly higher impedance (55 ohms vs 44 ohms), and for me the difference in volume was noticable. The AKG's do reach an acceptable volume straight from my iPod, for me at least. I found both very comfortable, but the SRH840 felt somewhat heavier and comes only with pleather pads by default, so that might be an issue for long listening sessions.
Either one would be a great choice imho.
I can't comment on the sound of the K240, but since I bought the K271 yesterday (which are a step up from the K240, but I would go for these if you can swing the extra cash), I can share some experiences with those. Mind you, they are not fully burnt in yet, so things might improve still. I mainly bought them for post-rock, ambient stuff, but I find them quite versatile. They definitely do not sound bad with rock, but for Foo Fighters you might want a bit more bass. Again it's certainly not bad, and with a bit of EQ it would be quite good I think. A decent burn-in would help as well. Also, according to the impedance chart on headphone.com, the impedance peaks at around 100 ohm around 100 Hz, so it would probably improve with decent amping. I listened to an acoustic song by them as well, which sounded excellent. (Listened to Bridge Burning, Everlong, Friend of a Friend and Hey, Johnny Park!, Bri;ge Burning 320 mp3, the others were old rips, in lesser quality, I don't listen to Foo Fighters all that much so I never bothered to replace them). If this genre is the main music you listen to, there are probably better cans at this price.
I can't comment on pop, since I have none whatsoever in my collection. As for electro, I don't really have that either, only some obscure stuff :p Jazz sounds supreme though!