I'm currently experimenting with a bunch of "lite/demo" sequencer packages. I think the answer to your question depends on your intended uses--audio only; drum machine and a few synth plugins; or full-blown techno loop production. You might want to visit the "hosts" forum over at KVR
http://www.kvraudio.com/forum/ and download demos before spending money on a program.
I use Mackie Tracktion 2 for pretty much all audio recording, but when it comes to MIDI/sequencing/looping it leaves a bit to be desired. I'm experimenting with a sequencer host called Energy XT that can work as a VST plugin to make up for Tracktion's deficiencies. At $150 I feel like Tracktion is a great deal (and quick to learn) if you don't need extensive loop-mangling capabilities.
I'm trying the Sonar demo. It seems pretty full-featured but I haven't scratched the surface too deeply.
For loop-based work, Sony Acid Pro 6 is a good bit of fun. There's a 30 day free demo, the program costs $250.
Fruity Loops feels a little bit toy-like but it's actually a very powerful tool for looping and sequencing. It's cool because there are several different packages available--you basically just pay for the features you need.
I'd like to try Cubase but
AFAIK there isn't a full-featured demo available and the forums I've visited are filled with complaints about how it isn't as good as it used to be.
I have a couple versions of Live (that came with two M-Audio soundcards I got) and it seems like it's the most intuitive interface for what I want to do (writing/arranging songs, working on loops and beats). Upgrade form the Lite version to the full one costs about $250.
I'm probably gonna go for Live (and keep using Tracktion 2) out of all these because I like the way it works and while I'm using a PC now, I'm thinking of getting a Mac laptop in the future and want a program that works on both platforms.
