Handbag advice, please

[MercenaryMum]

I need a new handbag, but as someone who has never really been that into handbags, I'm desperate for some guidance by those with better style sense than me (which means pretty much everyone).

Previously, I've had several cross-body type bags in different patterns (mainly from White Stuff), but my DD2 is severely disabled and I've decided that I need something bigger to fit her essentials as well as mine. However, I don't know my hobos from my shoppers and feel at a complete loss for where to start my search.

Also, although my default for leather handbags over the years has always been black, we now live in a warm part of Australia. Is it OK to have a black bag in the sub-tropics?

My requirements are that it needs to be big, have a zip or snap closure so everything doesn't spill out, a long(-ish) strap that I can put over the handles of a wheelchair, and looks at least somewhat stylish. I'm happy to pay for good quality, but brand names aren't really important.

Any suggestions? I would love some advice and links to get me inspired! (UK links are fine - if the shops don't post overseas I can always search out something similar here).

If I had any way to justify a new handbag, here's what I would be eyeing up. Good size, practical, smart-but-not-formal. There's a tonne of leather backpacks knocking around at the moment, but there's a slightly unfinished-cool to these, and all those colours! My choice would be the dark green.

www.houseoffraser.co.uk/Jigsaw+Blake+backpack/252082602,default,pd.html

Have a look at Kate Spade, Coach, Jigsaw, Radley, (though MN love / hate it) and Michael Kors, and imo avoid black. Tan goes with everything but there seems to be a love of teal/ green this season and bright blues.

Try Fossil. They have some lovely big tote bags.

Thanks for the suggestions! MrAliBongo I do like the look of that one - in fact most of the colours are nice. A backpack style would be helpful since I can sling it on my back if I need both hands free to deal with DD.

I'll have a look at the other suggestions and stifle my instinct to get anything in black. I did have the feeling it was too dark for a warm climate (especially as I work from home, so it doesn't need to be business-like).