<p>I don't expect a straightforward silver bullet answer to this, but what are the best practices for ensuring good performance for SharePoint 2007 sites?</p>

<p>We've a few sites for our intranet, and it generally is thought to run slow. There's plenty of memory and processor power in the servers, but the pages just don't 'snap' like you'd expect from a web site running on powerful servers.</p>

<p>We've done what we can to tweak setup, but is there anything we could be missing?</p>

Just a few ideas...
Is displaying your pages as slow when doing it from the Server or from a Client? If slower from client, do check your network.
Are your pages very "heavy"? (means, many elements, web parts and so on?) Than maybe it's normal.
Have you noticed they load slowlier since you've add one specific web part? Maybe there's some issues with that specific web part (for example, it's accessing to a document library that has many -thousands of- documents). If that's the case, try to deactivate that specific web part and see if the performance works better.