ok, this is good. so propane and natural gas are interchangable? are there any brands i should be looking for, or are they all the same?
interchangeable yes, so long as you get new orifices, although natural gas grills tend to be stationary for pretty obvious reasons
weber is a great choice. I'm assuming that if you are using an existing gas line, your grill is going to be pretty stationary and with that being said, I'd stick to a stainless steel model if possible. This is unless the area your gas line is located is very well sheltered from the elements.
if you have existing counter space as in a cooking island already there, I'd look into just getting a grill head to attach to your existing space. Bull Outdoor and Lynx make outstanding products but are not cheap.
as has been pointed out, the weber genesis is a fantastic model but it is going to go for around $750 and up unless you find one used
you can always get a less quality one but you do get what you pay for and being in the elements takes it's toll quickly on things that aren't made with quality