RP vs PVP characters?

So this is probably a stupid question, but I might as well ask.

I don't have any prior experience with GW, but the trailer for GW2 sparked my interest, so I decided I might as well look into it since I'm sick of my current MMOs. So I downloaded the trial, and noticed that when I created a character there was a choice between RP and PVP only (which was not accessible on a trial account). Now my question is, what is the underlying difference between the two. If you chose a RP character can you PVP with them later on? If you choose a PVP character are they unable to complete the PVE portion of the game?

If anyone could shed some light on this I'd appreciate it.

PvP only characters are just that, they can only do the PvP portion of the game.
PvE/RP Characters can participate in PvE and PvP. PvP characters have a significant advantage in PvP as they have easier customisation of skills and equipment, PvE characters can get to the stage where they are as strong and have the easiness of customisation a PvP character allows, but this can take a reasonable amount of effort.

PvP characters start out with max level and armor, so there is no need to level to be able to have max stats characters that can participate evenly in PvP.
PvE characters are generally better if you just want to do PvP casually.

If you chose a RP character can you PVP with them later on? Yes.
If you choose a PVP character are they unable to complete the PVE portion of the game? They have no access to any PvE content that is correct.

The tradeoff is that rolling a PvP character gives you a panel that lets you make armor and you start with all unlocked skills that you have gained.

While this doesn't seem very important at first glance, PvPers who do not like PvE the ability to roll a max character they can play with when times change and metas shift is what makes this game so amazing. Any other mmo you'd have to grind a new character to max level but in this you can simple make the armor you want, pick the skills you want, and go in

The time/money it takes to gear up a PvE character for PvP fully usually makes them unfavored in mainstream PvP since every single little thing gives a smaller advantage that adds up and people don't want to go in with any handicap.

It was told here, but I am not sure clearly enough - PvP character has free acces to all skills/equipmnet you unlock in PvE. So nearly everybody playes PvE with one character and PvP with other. All new skills and unlocked equipment is immediatelly available to PvP character. Where it differs - equipment you buy in PvE is not unlocked (you need to get it unidentified and identify it). On the other hand you can unlock skills/equipment/heroes for PvP using Faction points (PvP reward). See Unlock at wiki.

http://wiki.guildwars.com/wiki/Roleplaying_character

http://wiki.guildwars.com/wiki/Pvp_character

Most would strongly rec you start off with a PvE character as it will let you learn the basics and unlock a bunch of stuff you can use on a PvP char along the way. GW PVP has an extremely steep learning curve. Most people who try to get into PvP before doing anything else get their asses handed to them.