Hmmm…your best best is to stay in Old Town. Don’t stay in the Marina – it’s too far from town and definitely not Nuevo Vallarta. Do you like to rent a car on your travels? It’s really very easy to drive in PV. I highly recommend renting a car during your stay. We like to stay in an area known as Conchas Chinas. Try doing a search with that phrase.
The times we’ve gone we’ve gone on an exchange with RCI (timeshare) and really lucked out by staying at the http://www.playafiesta.com/ ask for Lindsey or Adam, tell them Kristi from Austin, TX referred you.
You must go eat at Boca Bento for dinner and say hello to Stewart the owner. He’s freaking awesome and the food is delish!
http://www.bocabento.com/
This restaurant is in the area of town I’d recommend trying to get a place. There are some small hotels in this area.
Another one to try but very expensive but sooooooo beautiful is http://www.haciendasanangel.com/
At least sneak in for a peak!! It’s amazing!
If you get a car, def drive to Sayulita! It’s about an hour/hour half North and it’s wonderful…like PV 30 years ago.
Have fun…Fall will be more comfortable temperatures. We ususally go in October or November and it’s still warm/hot.

good advice above. We ALWAYS stay in old town -actually we have a time share there. It’s the best place to be, especially if you’re not into the all-inclusive deal. Old Town has a “real-Mexico” charm to it with small, quaint, cobblestone streets. It is quieter, but there’s ton to do within the district. It’s within walking distance of downtown and the malecon, and we always here that these are the beaches where the locals go – which says something of the the purity of the area. You can’t go wrong with any hotel in this area I don’t think. Something we discovered last time was the bus system. We actually took the bus to Sayulita (which is indeed amazing!) for $4 per-person round trip and did some surfing in this quaint and untouched surfing village. The buses around town are about .50 per trip and come all the time. And it’s a great way to do the local thing.

As for time of year – Summer is hot and HUMID so if you can your trip will be much more enjoyable in the fall (winter is the best!). We went last year in mid-Sept. and that was still a bit hot/humid. If you go in the right time of year – it matters much less where you stay since you are in your room so little anyway – there is so much to do!

It’s a bit expensive, but you have to at least once take a water taxi to Yelapa and hang out there for a day. It’s a perfect little beach village to the south that is only accessible by boat. It’s great for lounging on the beach sipping your drink of choice or for hiking through the rain forest to a waterfall destination. For a cheaper variation,take one of the all-day “booze-cruzes” that will take you snorkeling, drop you off at a similar beach village, provide breakfast and lunch while en route, and give you all the free drinks you could want. All of this for about the same price as the water taxi itself! The crowd is never really our crowd, but the price/experience is too good to pass up.

Have a great trip!

The best hotel is the place we stayed – Hotel Molino de Agua. It is an old mango plantation in the middle of the romantic zone downtown. There are these individual cabins, and the ‘hallways’ to the hotel are just outdoor paths through the mango trees. The location is one the beach and in the middle of downtown. You get to be in the middle of the busy city, but nestled in a tranquil environment. This place is perfect.