To switch or not to switch?

I've been using my iPhone - a very basic model - for about a fortnight now, and I'm completely blown away by it!

I'm also in the market for a new laptop, because my current one is creaking with age.

Then again, I'm sick of error messages, crashes, endless reboots and registry errors.

Perhaps the thing I'm most sick of is the frequent slowing down almost to a standstill while my anti-virus software does whatever it does; am I alone in thinking that being monitored by anti-virus software is almost as bad as having the virus itself?

All of the above points to making the switch to Apple.

And I would, and I'd use iWorks and all that other good stuff and not be one of those people who buys a Mac for its looks and then installs a parallel OS to use all the software that causes the problem in the first place.

I do, however, use certain killer apps that are the very things that make me so productive, and they might ultimately stop the switch to Apple.

The first is Outlook - OK there, because Microsoft produces a Mac version.

The second is Business Contact Manager - vital to me, but I've found a Mac alternative, so that's OK.

The third is Personal Brain. If you've never seen it, Google it - you'll thank me for it. Fortunately, PB is available for Macs too, otherwise that would be a deal breaker.

The fourth and final killer app, and the one that is a deal breaker I think, is OneNote. I don't even necessarily have to stick with this app - I know that Apple have something similar and I could happily live with that. However, the single thing that boosts my productivity more than anything else is the ability to handwrite notes straight on to my tablet laptop. That, I cannot live without.

So what am I to do? I plan on buying a powerful beast that will last me years rather than year, but I need that handwriting function.

There are several great convertible laptop/tablets out there now, sporting solid state hard drives, 8Gb RAM and Intel i7 processors, but ultimately they will keep giving me the same Windows OS grief.

A MacBook Air is very tempting, but I can't handwrite on it. An iPad screen is too small, and the OS wouldn't let me load the programs I need.

Rumour has it that Apple will launch a convertible laptop, but that could be ages off, and what if it turns out to have a disappointingly small 10.1" screen? I want portability, not a squint. My current tablet is just over 12" and that's my benchmark, give or take half an inch.

So do I wait and hope Apple come up with the (near-) perfect answer for me, or do I go out and buy a mega-powerful convertible laptop PC now, and so turn my back on Apple for at least another four years?

Or is there another alternative I'm missing?

I'd love suggestions from all you Apple aficionados out there - preferably before my PC gives up altogether!