Let me start with agreeing with the posters who tell you it will be very busy; longer than usual lines and possibly not the ideal time for a first visit. However, if your dates are not flexible I wouldn't let that stop you from coming to experience all that DL has to offer, just be prepared to deal with crowds.
Also DL is different than WDW in the proximity of hotels. If you have seen "off-site" hotels at Disney World you know that can be a few to quite a few miles away from the parks. At DL, some of the "off site" hotels are literally closer to the park entrance than the on-site ones. So proximity would not be a reason to choose on-site and there are several cheaper hotels in the area: Candy Cane, the Ho-Jo, the Carousel that get consistently rave reviews on this site and you can book a room for $80 a night or substantially less.
But, that doesn't mean there are no merits to staying on site. Most Disney cast members do such an amazing job of helping you experience the magic everywhere you go and staying onsite will keep you surrounded in it the whole time you are there.
If money were "no object" to you, the Grand Californian would be such a unique experience. Especially if you pay for the park view and literally look out over the theme park, there's nothing like this even at Disney World! It is somewhat similar to The Wilderness Lodge and definitely the most "Disney" as far as theming.
The Paradise Pier to me has the least amount of Disney touches. Has been recently renovated (and I haven't seen it since it was) to have a beach like atmosphere. Here you could have a view of California Adventure as well.
I am going to be at Disneyland next Memorial Day weekend as well and I have chosen the Disneyland Hotel. I have wandered through this hotel but never stayed there. It has tropical "gardens" and waterfalls. The Neverland themed pool of Peter Pan just says Disney magic to me and the rooms have "pixie dust" in them. I am also 30 something and my husband and I plan to enjoy and have no kids.
We chose to book our package through
AAA. I wouldn't say that's the cheapest way to do it, but we will get to take advantage of unlimited fast pass and early entry so that seemed like a perk for a holiday weeekend. Good luck with your deciding!