Moving to an iPhone would probably be a mistake, especially as you are coming from a (presumably Android) HTC. A lot of people I know who have moved over to Apple have only complained about how locked down it is. All your settings are very limited, everything has to be done through iTunes, you can't use widgets and apparently even changing your ringtone is a pain in the @r$e.
Don't know which phone you had, but the HTC One X is an excellent phone, as is the One X+, alternatively the Samsung Galaxy S3 or the Galaxy Note 2 (best phone out there right now) are both top notch. The main benefit being that all you contacts, etc are in the Google ecosystem already so setting everything up is remarkably simple.
You say you lost all your numbers, but these should all still be in your Google account.
My contact is up soon and I am considering an iPhone. I want 3G and have become a bit of an Apple tart ask have a Mac air and ipad. My HTC needed a new chip so I lost all my numbers and notes...I therefore want something reliable and everyone I know with an iPhone is happy with it. I am on O2 but would consider moving to another network. Help me...will need a shop to help me transfer data and help me work the damn thing as I am not someone who finds technology intuitive.