Statistics packages that don't increase load
 

I would be interested in hearing what other big boards are using for statistics packages. Most of them seem to calculate on demand and cause a huge load spike.

There's very few reasons to be using an on-server analytics tool which generally rely on log-analysis for reporting. Cookie & Javascript based solutions like those offered in ASP model analytics give you far more power with just about no server or visitor load impact. If you're looking for a low cost solution, Google Analytics is your best bet. For something more robust with more ability to dive into data take a look at Omniture, Visual Sciences, and HBX.

What Ted said.

google Analytics is awesome, i've disabled my server stats programs and just use analytics for everything now.

We are currently using a package called Deep Metrix, it was aquired by Microsoft, but it still works. What it doesn't give us is board oriented statistics, most viewed threads etc.

You can get most viewed threads out of your AdminCP

What other kind of stats are you hoping to gather?

Most Viewed threads is hardly robust analytics... At the very minimum a forum owner (especially a BB owner) should be looking at major KPIs including traffic, time spent on site, pageviews, conversion rates as well as major traffic reporting like top viewed pages, top paths, exit pages, landing pages, inbound traffic sources and search queries. For more advanced sites trying to maximize their profit, mirroring up these reports with various user segments using behavioral and known data can really take things to the next level.

I'd go for a solution which analyzes the (apache) logfiles offline.

Just add a little more ram and your server will handle it just fine ;) Another great idea would be adding google analytics to your sites and disabling ANALOG.
Then, just set the stats program to run at a time when you get the less visits

I 2nd google analytics, it's a great tool. I like hittail.com as well to track incoming search request.