Don't buy Final Cut Studio!! It's a dog on rendering. The code is bloated and doesn't fully recognize the power of multi processors or extra ram. If that's not an issue for what you plan to do, then just realize that Apple is over-due for a new release and you might get stuck with an upgrade fee if you buy too soon. Not a good time to invest in their software.
FWIW, I just tried Adobe Premiere CS 4 on my MacPro and it renders faster than Final Cut Pro. In many ways, Adobe has surpassed Apple in the video market. Apple has been busy with iPhone and consumer products and left their pro line to languish. Not Adobe. The Adobe CS4 video products are really nice. Premiere, After Effects, Flash, Soundbooth, etc. Check it out.
A statement of the truly misinformed...
FCP is a solid platform that has enjoyed nearly a decade of consistent industry support. There's tons of third party plugins, hardware, etc. engineered for FCP integration. You can't always say the same thing about Premiere. In fact, Premiere didn't truly start getting good until CS3.
1. A dog on rendering? A lot of rendering operations in FCP are multiprocessor aware to varying degrees. Many plug-ins are as well. Example of my CPU load while rendering a long credit roll sequence with the CHV Credits v4.1 plugin in FCP:
Somehow, I think an average 80% load across all CPUs would qualify as multiprocessor aware.
In Compressor, rendering a batch with a virtual cluster set up in QMaster brings my 8-core Mac Pro down to its knees (95-98% CPU utilization across all cores).
So, I call BS on this one.
2. Tackling the subject of RAM, the Mac version of Premiere CS4 is still 32-bit. It's 64-bit on Windows Vista 64 only. So here, you have the same 4GB memory window that holds back FCP. I don't expect either application to become 64-bit until Snow Leopard and that's when we can really start making comparisons...
3. Yes, we've been waiting a while for FCS3. Everyone knows that. But that still doesn't make FCS2 a poor value. For example, FCS2 comes with Color, which was once a standalone application known as Final Touch that sold for $20k. There is no such application in CS4 Production Suite. There's trade-offs to both suites, really. For example, CS4 Production has After Effects, a $1,000 application purchased separately. Other than those differences, I'd say the playing field is starting to level. Adobe isn't surpassing Apple on the Mac platform per say - it's merely trying to stay competitive. This should get more interesting as time progresses.
But getting back to the OP's original question, I would venture to say that Final Cut Express is a good starting point. Its editing interface is identical to FCP, but has fewer features, lacks support for professional codecs and doesn't come with as much bundled software. But for $200, you WILL NOT find a better NLE on the Mac. Period.