Here's what you need to do. Get both cameras in your hands. Play around with it. Its a point n shoot.... but there's xtras options. So play around and get the feel. Interface is important too, so to be sure you won't daly too long and miss pictures. 5mp vs 6mp is abt no diff. You'll get your 8'x10' sharp n clear on both cam. You want diff, go 8mp.
Another point to consider, more pixels = more noise. OIS is an xtra that is nice, useful too but not essential. Battery life on the Lumix is much better than the one on Ixus, but Ixus has a viewfinder thou kinda smallish, but it's there. For some, knowing that it's there means a great deal, at least to me it does.
I know, it's always like this. The more you know, the more undecided you get. That's how helpful this forum/discussion thing is. But at least there are grounds for the undecision. Anyway, first thing first.
Get down there, get a hands on experience on both. Bring a friend that knows stuffs. A hard-selling salesguy can easily sell carrots to a monkey when it actually wants bananas.
Both are good cameras, really. Its just how they felt on your hands and how easy it is for you to use them that might make a diff.
Good luck, there. And after that enjoy shooting. You can carry these babies anywhere. That really is a big plus point.