I'm sure it was a top-end phone back in the day. But I think a ten year old 2G/3G phone isn't really worth anything now, and probably won't really be usable and supported by much. Keep it sealed, it might be a collectable antique one day.

 

It's 10 years old.
Hang on to it for another 15 years and maybe it'll be worth something

 

If it's sat sealed for 10 years you probably need a new battery for it anyway - leaving the battery to self-discharge for a decade won't have done it any favours.

 

Unfortunately it was never a top-end phone. Although "Desire" was HTC's flagship brand in 2010 and 2011 (Desire, Desire HD, Desire S, Desire Z) in 2012 HTC changed their branding: the 2012 flagships were the One X and the One S, while the Desire C, Desire V and Desire X were budget models (after which "Desire" always indicated a low-end HTC).

(My wife had a HTC Desire C. It really was hard to believe that that POS came from the same people who a few months later made the HTC One - a real shame that they lost their way so badly).

I still have the original Desire in a drawer, but I as it was heavily used I don't hold out much hope of it being collectable (though maybe having the long-discontinued and always niche Redux 2 ROM on it will make it more unique? I doubt the fact that it is my own customisation of that ROM will add to the value though).

 

keep it.....it should make for a good mp3 player.

 

Though less so while it is sealed