Yeah, out of all of those which you listed I only use Swype. I've stock with whatever the default launcher has been with my ROM flavour. For me and what I use my phone for it has more then enough horse power to not allow me to justify going to a new phone, you on the other hand sounds like you want all the bells, whistles and thensome. Enjoy the GS3 when you get it, as it sounds like you'll be going towards it when it's released.I don't have many background apps running either, but multitasking definitely isn't possible, at least not at the level that new phones are able to do so. The One X (just as an example) is able to jump in and out of applications like no tomorrow. Pretty much instantaneous. On my phone, most apps take a few seconds to "load". I suppose part of my problem is that I use Swype (~14MB) and Nova launcher (~37MB) with Beautiful Widgets, Google Reader and baconreader widgets on my home screen (~24MB). But that still leaves me with 180MB of RAM free, but I guess it's not enough.
I've tried custom kernels too which bump it up to ~390MB of RAM available and even include support for swap and zram, and they actually seem to be even laggier than the stock CM9 kernel. They work great for the first couple hours, but then they get extremely slow.