What do you buy for a bridal shower?

If I know they drink, I will buy them nice wine glasses, a cork screw and a bottle of wine.

Last weekend I went to a shower and knew that she loves martinis and the groom loves whiskey. So I bought her a set of martini glasses, for him a set of whiskey tumbles, and then found some nice monogramed coasters that I knew would work in their bar area.

Bridal or baby showers, I'm a stick to the list and what my budget can handle person.  Beyond that I tend to stick to the practical with a little pretty/fun stuff thrown in if my budget allows.  

Picture frames, pretty lamps, candles etc are all fun but you really do need a toaster, knife set, pots and pans and sheets etc.  You can live without the other stuff and save up and buy it.

ETA-most of the bridal showers I've been to are for younger couples.  Even if they have been on their own already, it's been on a tight budget, college style decor etc.  So they don't have much and what they do have is not very good quality.  I can only think of twice it was for a more established bride.  In that case for one I gave a picture frame (I was still a very young newlywed with little money) and I don't remember the other.  

Pyrex, Corningware, or Le Creuset. Twenty years from now, they'll be vintage!

It totally depends on the person and situation. How much I plan to spend, whether I'll be attending or not. Do I have to have it shipped somewhere? How well do I know them? How much stuff do they already have? And often, what's already gone from the registry.

If they have already received (providing the registry is properly updated, which is an enormous assumption, I know ) 11 of 12 requested place-settings, and most of the accessories to the china set, I would likely want to see what i could do to finish off that category or the 12 place-setting, etc.

If I see a comforter has been purchased, but the shams and dust-ruffle have not been, I'd go for those. That kind of thing.

If there are a bunch of "left-over" items that people seem to be ignoring, I might buy all of those, even if they don't go together, just so that the couple has them.

Just out of curiousity, do you double check if they are changing names to have matching last names? I know from wedding planning that there are a lot of brides out there who would be super offended to receive a gift like this because they weren't changing their name after the wedding. I didn't, I wouldn't be offended but I would question the assumption that I was. It was actually rather eye opening to hear from brides who found this assumption to be a major offense and now when it comes to stuff like monograms I never assume for this reason. 

It depends. Relationship, age, first marriage, kids already, etc. Younger couples I tend to go practical- sheets, towels, mixing bowls. Older couples I get more memorable things - the teapot from their china, a place setting of china or silver, etc. But either way, I think it's better to pick something from the registry unless you have a close enough relationship to know with certainty what they need or would like.

I guess I should answer the OP. I usually buy something off the registry (let's say a pasta press) and then a cookbook and an accessory that might (ravioli mould, bench scraper, etc). I don't put a lot of thought into it to be honest, I look for something on the registry that makes me say "oh cool" and run with that. Too much thought can be a bad thing.

This is what I do too - find something in my price point and get that

Don't overthink it. She wants all of it, so anything from the list will be appreciated.

I typically go for something functional from the registry. I like to shop at Bed Bath and Beyond because I always have a 20% off coupon and they have a wrapping station.