Pros: tremendous bass response; excellent
Cons: they have been replaced with the northridge series and are hard to find
These bookshelf speakers are incredible. They consists of 10mm horn tweeters and 8" rubber-surround woofers. They're rated for up to 150 watts per speaker and are video shielded making them great for left and right speakers in a home audio/video system.
I'm currently using 4 of these (left, right, left rear, right rear), a JBL Northridge center, and an Onkyo receiver for my home audio system. The bass from these four HLS810s is good enough that I don't even need a separate subwoofer.
I was planning on buying more expensive floor standing speakers, but after listening to these I realized how ridiculous that would be. These speakers produce better sound than anything in the price range and many others that are much more expensive.
The only negative aspect about these speakers is that they are no longer in production. The new series (northridge) came out and has replaced the HLS speakers. The comparable northridge speakers (N-28) are also excellent, but cost more (~$300/pair). They are very similar but have dome tweeters instead of the horns.
I would highly recommend these speakers to anyone looking for the best speakers for a relatively low price. They're hard to find but it will be well worth it if you do. I got mine for $125/pair!