Best blogging platform / blog+website integration & other quests

I'm not sure these questions are the 'right' place or indeed if it's been answered here - I couldn't find anything..please feel free to move it appropriately, C4.

- Is there a general consensus these days as to what is the best (non gaia) blogging platform?

- Is it possible to post to a Gaia blog and another blog at the same time? (and if so, which platform?).

- I'm developing with a friend a new website (joomla). This site will be writing specific, and I plan to have a blog as part of the site.

I'm now wondering if it's an idea to actually have a completely separate blog. I've been advised that publishers/agents will possibly give a writer more of a look if they can show an online audience. I suspect this is mostly possible through blogging, and I'd like to create the blog that can develop the biggest audience.

Does anyone know of any drawbacks to having a blog integrated into a website ( especially a joomla site, which, I believe, uses wordpress?), or does it make no difference? I've seen some blogs embedded into websites, and they often feel kind of lost - not part of the blogosphere, so to speak.

All advice GREATLY appreciated.

thanks!

Sandra