Yeah - I don't know if there's any documentation on large deployments ... I guess the question would be: what is a large deployment?

I'm sure you've seen this one:
http://manual.b2evolution.net/System_requirements

300,000 hits don't sound too bad. how many hits per minute? what type of pages do you have? if pages are tiny (some text & pics) 800KB - I would say that's pretty standard for a blog w/ pictures.

Perhaps we can use your epxerience to document a 'best practice' document.

We figured out that a lot of issues were I had 14 posts on the main page and TONS of graphics/ads in the side bars. This had always caused my site to load slowly. I cut the posts back to 8 and cleaned up the side bars and this helped alot. We also set up a proxy server since my site is only updated about 15 times a day and so far it is working like a charm.

I would be happy to help but I don't know how much I would be I am really new to this and just figuring it out as I go!

300.000 hits per day is great !

How much posts do you have in your(s) blog(s) ?

Are you using mysql 4.x or mysql 5.0 or mysql 5.1 ?
What's the size of the database ?

Innodb is great in term of performance. Sometimes MyISAM is better, sometimes no.

Which version of Apache are you using ? Same question for php.

And which version of b2evolution are you using ?