Just as we expected, the HTC events turned out to be about the company's new flagship - the HTC One.
HTC One features a 4.7-inch Super LCD 3 display of 1080p resolution (that's 469ppi). It should be able to match the image quality of the Butterfly's unit.

The One is powered by the latest Qualcomm Snapdragon 600 chipset (the same ticking inside the LG Optimus G Pro) utilizing a quad-core 1.7GHz Krait 300 processor, Adreno 320 graphics and 2GB of RAM.
The camera of the HTC One sports a 4MP sensor and 1080p@30fps video recording (with HDR). The sensor has what HTC calls Ultrapixels, which are much larger than the regular smartphone pixels and promise vastly improved per-pixel quality and low-light performance. The smartphone also offers gyroscope-based Optical image stabilization which should come in handy for video recording.

HTC One
The HTC One will have 32GB or 64 GB of non-expandable storage and rich connectivity settings including LTE, NFC, Wi-Fi a/b/g/n/ac, Bluetooth 4 and GPS with GLONASS.
HTC One will launch running on Android 4.1.2 but the 4.2.2 update is already in the works.
The new flagship is made out of aluminum and is about 9.3 mm thick. It has stereo speakers at the front with impressive 93db loudness and a 2300 mAh non-removable battery. Also, its Power/Lock key on top is transparent and doubles as an IR port to control home equipment.
HTC One will be available in black, red and silver colors and will launch in March this year. HTC has already made deals with 185 carriers worldwide including USA's AT&T, T-Mobile and Sprint; all major UK carriers and many more. There is still no info on its retail price, though.
You should check out this article for live photos of the HTC One, garnished with our first hand impressions of the device.