If you're looking for a cheap mid-to-high end smartphone from a reputable band, the Sony Xperia, not to be confused with the Xperia S tablet, is not a bad deal.
It is available from BuyMobilePhones for only £15.50 per month on a two year contract from Orange on the Panther 15 plan which gives 50 texts, unlimited texts, 250MB data, BT Openzone WiFi and one free Swapable.
At £372, the total cost of ownership of the contract is not much higher than the price of the unlocked handset alone.
As for the Xperia S, it packs a dual-core Qualcomm Snapdragon MSM8260 SoC clocked at 1.5GHz, 1GB of RAM, a 12-megapixel camera, 1GB of RAM, a 1.3-megapixel camera, 32GB onboard storage, a 4.3in 1,280 x 720 pixels display with Sony’s Exmor R Backlit sensor, and Android 4.0 Ice Cream Sandwich. Unfortunately, the handset lacks a microSD card slot.
The Xperia S has recently been replaced by the Xperia T, which offers a minor upgrade from its predecessor. It is still one of the more affordable smartphones on the market with an HD-ready display.