I haven't used tigerdirect so I don't have any stories about them, good or bad. I have had great luck with newegg and have been willing to keep using them even though they're not the cheapest out there.
As for the difference between the types of crucial memory, the regular crucial PC3200 memory is rated to run at "stock" DDR400 speeds with memory latency timings at around 2.5 3 3 8 or so. Ballistix PC3200 sticks are rated at 2 2 2 6 or 2 2 2 8 at ddr400, and can be overclocked pretty high with no problems. The regular crucial stuff may be able to be overclocked with relaxed memory timings, but they're not really intended to be overclocking friendly. If you don't plan on overclocking your system, then you're just fine with the regular crucial pc3200 because at stock settings, the timings aren't going to make that much of a difference. You only get the big gains when you combine fast timings with a hefty FSB overclock, and that means you gotta spend some serious $$$ on really good parts.
