For either:
a) Quality of sound.
b) Value for money.
c) Features.
HTC accessories official site has these at £30
http://www.htcaccessorystore.com/uk/p_htc_item.aspx?i=251845&phone=251837 Any good?
If you are looking for a seriously top quality IEM (In-ear), go for the SoundMAGIC E30 Earphones, £39.99 from Amazon UK - combine these with Comply Tx-400 tips (amazing memory foam tips which expand to perfectly fit your ear, blocking outside noise and noise cancelling!).
I'm a bit of an audiophile, have some serious headphones including sennheiser ie80 (£250), sennheiser HD25-1 mk2 (£300), Creative Aurvana Live (£200) - all amazing, but they have there place (HD25's for my music studio) etc.
The Soundmagic E30's are seriously AMAZING for the price, and I mean amazing - I've got six pairs of headphones, and the E30's I use every day, brilliant for trains, buses etc.
Combined with the Tx-400 comply tips, you will NOT FIND anything even close to the range and quality delivered - they are, IMHO, close to being my first choice over the ie80's which cost me £200 more!
No mic or control buttons, which is great. Mic's and buttons are s#it and destroy your listening experience.
Trust me, you get these, you will be delighted!