How do YOU provide site wide search?

The problem is that as your model gets more complex it becomes a real pain to implement what (to the client) is just a "simple" text box and search field.

One approach to this is to write a search generator which takes metadata about each object and uses it to automatically generate the display mappings and the like, but that would be a chunk of work and I'm pretty backed up right now.

The other approach I'm toying with is just either a third party service or a downloadable script that treats your site as a collection of static pages, spiders them and provides a simple Google like listing. The strength of this approach is that it better matches what people expect to see - a way to find "pages" in your site with the search terms rather than a way to access content items matching the search terms (the content items often loose context being accessed by search).

Just to clarify that last point, what does the "back to category" button do on a product page if the product is in n-categories and you accessed it using a verity search? All of those kind of contextual data provide dilemas when using a "search each table with verity and collate the answers" kind of approach to searching content items rather than just spidering the site.

Of course, there is still a place for an "employee search" or "product search" that would clearly want to use either a db query or verity, but what do you think of just using a spidering service or product for your site wide search and does anyone have any good recommendations for solutions in the hundreds of dollars or below that they've implemented successfully in the past?