Under $50
NuForce NE-600X ($25)
NE600X is one of the best build $25 IEM can you ever hope to buy and it has good SQ to match its build, excellent for gift and those in tight budget.Warm mid, big bass and an overall easy going sound.
Astrotec AM90 ($45)
Astrotec specializes in making budget bang for the bucks headphone and AM90 is their implementation of the Knowles Siren balanced armature and probably the best one to date. Mid centric while still maintains a very decent soundstage.
Brainwavz R1 ($50)
The new dual dynamic from Brainwavz can be a bit too bassy and veil with the stock big flanges eartips, but once you have the stock single flange on it, the treble will jump out and the whole sound signature becomes a lot more fun and enjoyable. Dual drivers for $50? I don't think you can ask for much more.
Between $50-$100
beyerdynamic XP3 ($58)
With a mild U-shaped FR curve that gives good bass impact and detail treble, plus a good soundstage to go with them, XP3 does a lot of thing right in its sound. While the flat cable and mild driver flex can be annoying some time, they are not a complete turn-off. If an U-shaped FR curve isn't your thing, there are still the more neutral and analytical XP2 and the bass orientated XP1 for the same price.
Sony MH1C ($80)
Originally intended for Sony's own Android smartphone, this headset has the SQ to compete with IEM much more expensive than its price tag might have suggested. Good bass, warm mid, smooth treble, it is as much about musicality as it is technically proficient. The best part is that it can often to be found for much cheaper price.
JVC HA-FXD80 ($100)
Not really an upgrade over last year FXT90, the new FXD80 however has a more neutral tone and less grainy upper vocal, making it a more versatile IEM than its older sibling. Not available on most part of the world, it does however can be acquired from Japan via eBay for around $100, making it some of the best deal of the year.
Between $100-$150
Rockit Sound R-50 ($120)
R50 is essentially a top-tier sounding IEM without any fancy housing. Warm, sweet yet fairly detail, it has almost the same technically ability as the VSONIC GR01, but in a cheaper looking plastic housing.
Yamaha EPH-100 ($130)
Huge bass and big dynamic is what defines EPH-100 as a fun sounding IEM. Don't get this IEM if bass is not one of your thing. But for those who don't mind lesser accuracy, the Yamaha can be a very enjoyable IEM to listen to.
DUNU DN-19 Tai Chi ($133)
Excellent build quality and a tunable sound signature is what gives Tai Chi the edge. By playing with the included eartips and back chamber air vent, it can sound either well balanced or bassy, all to your own liking.
Between $150-$500
T-POES H-100 ($170)
As a dynamic+balanced armature hybrid IEM, H-100 gives sparkly detail and well texture bass that makes for a good upgrade over the same V-shaped sounding Triple.fi 10. If you buy straight from the Korean manufacturer, you might even get it cheaper.
TDK IE800 ($200)
While mid and sound stage are the strength of this dual dynamic, bass and treble are not shabby either. IE800 truly defines what musicality should be and its vocal is as magical as you can hope for. This is an IEM that can match its top-tier sibling, the BA200 that has been recommended last year.
VSONIC GR01 ($210)
GR01 is another IEM that can match its well received sibling, the GR07. While it doesn't go as deep in bass and not as airy, GR01 does has a more rounded warmth and body to distinguish itself as one of the best dual balanced armature IEM around, rivalling even some of the triple driver variance with ease.
Beyond $500
Lear LCM-5 ($900)
This 5 BA drivers custom from Hong Kong can match the performance of any top custom IEM in the world. It is warm and sweet with good end-to-end extension, and can do sub-bass as it can do mid texture or treble sparkle. But with the optional 'monitor adapter' and a portable amp, it can turn into a highly accurate and analytical sounding IEM as well, if that's what you fancy. That kind of versatility and technicality are what sets LCM-5 apart from the crowd, where you don't have to settle for just one sound signature.
Odds and Ends
This is where I place those that are not quite ready to make the list, but still deserve a mention
RedGiant A03 Ossicle ($150)
As new comer in the IEM world, RedGiant makes a fantastic sounding dual dynamic. The only problem is that it only fit those who are larger outer ears comfortably, making it a less realistic choice for most.
Accutone Taurus ($60)
The headset turns headphone manufacturer Accutone has its first crack on bass tunable IEM with the Taurus. The overall impression on sound is quite positive, especially for a $60 IEM. However, the overall build quality still has room for improvement. The bass tuning mechanism certainly can be more delicate. But for $60 on a bass tunable IEM can actually work, the Taurus is still quite remarkable in its own right.
Blox TM7 ($140)
So you like earbuds instead of IEM? Then Blox TM7 is the one earbud that you should be looking for. Yes, it doesn't look quite like a $140 earbud and yes, it seems to be hard to find. However, I can assure you that it is that good sounding to worth a recommendation. Blox like to produce their earbuds in very small batch with a very slow pace so they are sold out almost as fast as they are put on website. If you rather go for brand name, the new Sennheiser MX985 is about the same price as well.