Ooh good idea about having 'thanks for comingses' for the guests Rae.

MG, I'll tell you how I'm doing mine, and my reasons.
No boys - because my DH is lovely and interested, but because I go to church, my friendship circle is quite large, and we wouldn't fit boys as well as girls in my house! Plus, he is a bit shy, so won't love it like I'm going to.

At my house, because I am 8 months and can't be stuffed going out anywhere!

My best friend is 'organising' it, she just got married, so I have taken care of invites, but made it look like they're from her. She wants to do games (because there will be people who don't know each other, I think games can make everyone feel like part of it), so she is organising that, and we will call some of my closer friends/family soon and ask if they'll bring some food. From my experience, people don't eat too much at these things.

A morning tea, because I hate weekend afternoon do's where it sorta ends up taking up the whole day. But that's just me.

Presents, because Anna's right, people bring them anyway, so we said on the invite that they're totally not required, it's more about catching up, but if they're stuck for ideas to call my best friend. And she'll work off a list, or suggest money.

Traditionally, someone else organises it for you, but that's because traditional baby showers are about 'showering' the mum to be with pressies! So that's like asking for pressies! But having a bbq, sounds fun, you could definitely organise that yourself.
And if you mention presents (if you know guests will get stuff anyway, and you want to guide them so they don't waste money on things you won't need), then you organise it, but write the invite from a family member or close friend who is happy to be the rsvp person!

Sorry for the long post, mine's just over a week away, so I'm kinda in 'baby shower mode' Anyway, you've got plenty of time, and, by the sound of it, lots of people who are looking forward to it, so it will be awesome, whatever you decide to do!