Anyone Have advice on blogging software?

So here I am blogging on my new laptop, which is also my oldest laptop. I picked it up cheap from a buddy of mine, complete with its tiny hard drive, slow processor, and long, long battery life. This will become my day-to-day writing laptop, so it will also be the platform on which I do the majority of my blogging. Now, I haven’t actually tried my blog software on this thing yet, but it is really, really slow on my other laptop, which is about three times faster and has a lot more hard drive space, so I’m not optimistic that I’ll be able to tolerate its performace here. Plus, I need a blog that better supports having multiple machines. It’s time to accept that iBlog is likely a dead end, and find an alternative. Maybe some of you can make recommendations.

Her are the requirements:

1) Able to composse offline and update later (absolutely not negotiable).

2) Can embed fancy html in the episodes, or can create custom episode templates easily (in minutes).

3) Can update from any computer (or phone).

4) Search-engine friendly URLs

5) Custom CSS for episodes based on category

6) category pages can have different display rules (some categoried display oldest to newest while others are newest to oldest, for instance).

7) Some way to automate transferring a very large blog, complete with internal links and lots of custom HTML in various episodes (intern?).

Dr. Pants recommended WordPress, which has a lot of people tweaking it alll the time, so that’s my front-runnner right now. I’m certain I could do all the above (except off-line composing, perhaps) using a fancy content management system like Drupal, which I know in an offhand way. It’s pretty darn powerful and pretty darn versatile, but to turn that into a working blog the way I like it might be a lot of work. I’ve used blogger a bit, but it seems quite limited for what I want, at least on the surface. The other online blog services seem to be similarly inflexible.

What offline editors are out there I could use? Are they going to be too limited, since they are made to be universal? How would they handle embedded images and custom markup?

So, I’m wondering if anyone out there has any suggestions.