Anyways, I figured I ought to bring up something that everyone can appreciate: Aggregated, organized, and easily-explained links for DIY speaker designs.
Zaph's B3S single-driver speakers:
These are single-driver speakers, which means that they're not going to be the all-time best for treble or bass. On the other hand, at under $40 a pair, they're also really, really cheap. They make very nice near-field (i.e, desk or computer) speakers, and are a very good option for HT satellites - especially the rear channels, which rarely carry high treble or low bass anyway.
Zaph's Silver Flute/Vifa combo
This is a pretty darn good design for the money, and Zaph has a reputation for nearly unbeatable crossover design. If you're short on cash, these are hard to beat.
These 2-ways use the BG Neo3 planar tweeter in a design similar to the Modulas. However, the tweeter is very, very different - many people prefer them. Both these and the Modulas are supposed to be excellent - and the price difference is not that huge (about $30), either.
Zaph's Bargain Aluminum MTMs:
This uses the excellent Seas 27TBFCG in an MTM configuration with two slightly cheaper woofers. They're very efficient speakers, and with a subwoofer, are nigh unbeatable for home-theater use.
Zaph's L18/27TBFCG 2-way
This is a 2-way by Zaph using the same tweeter as the BAMTM, but with a high-grade Seas L18 aluminum woofer. Testing has shown that these are over 95% as good as their more expensive Excel-class cousins, but at half the cost - and many builders will testify to this design's quality.
Lou's Zircon towers
The Zircon is essentially the "big brother" of the Cryolites, using a more expensive Vifa woofer in place of the Dayton. They're also much larger, being traditional tower-style speakers, but have better bass as a result. I'm afraid I can't give any testimony other than that of the designer, but his other design featuring the tricky-to-use Neo3 (the Cryolites) is extremely popular - and it's hard to go wrong with something which compares well to the $2,000 a pair ACI Jaguars.