before you decide, you should do alot of research on the root process. this is not a difficult phone to root, but its not as easy as some are to do. i would suggest looking at the very useful sticky threads here on this site, and you can do some extra reading over at xda-developers in their wildfire s forums as well.

rooting doesnt change anything about the phone, other than giving you "superuser" permission. this is comparable to running a windows program as an administrator. after rooting, it does open up a world of new tweaks that can be applied to the phone, such as ROMs (custom OS versions), and overclocking (speeding up your processor above the factory limits). you can also get programs to give you more app space (apps2sd, link2sd) and save your battery when the phone is in standby (setcpu). the only real cost is that rooting WILL void your factory warranty, but the process is not illegal and can be undone if you need to return the phone for service or just dont like the root access.

as far as actually going through with the root, there are some basic things you need to know about your particular device. there are a few different versions of the wildfire s, or marvel as the official HTC name goes. the CDMA versions (marvelc) can be set to S-OFF and rooted with little complication. the GSM/SIM card versions (marvel) are a great bit more difficult, since the hboot comes locked on all marvel series phones and GSM S-OFF cannot be currently done without purchasing (or at least finding someone who has) an XTC Clip. there are several threads at XDA about *possible* solutions without the XTC, though i cannot confirm any of them as working since i was fortunate enough to get a CDMA version.

once you get everything in order as far as the phone info goes, i'm sure there are several people that will give the best advice they can to help you achieve rooting. if you have any more questions, then feel free to ask, i'll be glad to answer them or send you in the right direction if i can.