Being relatively new myself, I can't offer as specific information as the fine people above. I've got a Garmin nuvi 265W that I loved. Please note 'loved'. Unfortunately, ours freaked out and froze up on us so we had to send it back to Garmin. Our replacement is due any day and we'll be back out on the trail.
My three bits of advice are:
1) Be sure to have a work related project minimized on your computer to pull up real quick when the boss comes in, because this is ADDICTING!!
2) Check out how to make your GPS paperless, by installing GSAK. You can get everything you need to know at this website.
3) Enjoy it!! My wife and I have been to places we didn't know existed and seen some beautiful sights!! And we've only found nine caches as of this posting.
Pretty much most people on these forums are friendly, so don't ever be afraid to ask questions!!
Enjoy and good luck!!