Folks tend to recommend what they know - I would suggest two choices:
1. If your friend are who you would work with, then there is a lot to be said for having the same software - for eg all the people I work with use Live as thei8r primary creation tool and it suits the way we make music, but it isnt for everyone.
2. Think about what you have, how you would like to work, what kind of music you want to produce and you think you may go about it, for eg:
a) If you are an accomplished musician who can play stuff more or less without fault beginning to end and so want to think in terms of laying down a part at a time, then a linear way of working may be best - ie logic, cubase, sonar etc.
b) If your more like the rest of us and tend to record little phrases etc and tidy them up and record more clips for more parts and then play around with them to get inspiration on where to go next, then a clip based non-linear way of working may be better - ie Ableton Live, FL Studio etc.
Another option if you down need audio in at all (ie not going to record acoustic/electric instruments or vocals) then something like Reason can be worth looking at.
If you are more of a DJ than a musician, where you idea of production is more about on the fly mashing, etc, then Ableton Live is your thing as well if you want to work with audio clips, or perhaps even something thats completely DJ orientated.
If hip hop then you may want a groove box like approach to recording looping and chopping them, in which case, FL Studio, Ableton Live or Reason + Recycle come to mind.
As mentioned before while reason is a great place to start for an all-in set of instruments fx and sequencer - there is a very finite boundary to it - in particular if you want to work with un-chopped audio - for eg vocals, then you need something else as well and workflow gets messy.
Have a think about the way apaches to creating music - and see if any reflect what you do, would like to do.
As stated, I use Ableton Live and how I generally work with it for from-scratch writing is as follows:
1st record some clips from my keyboards (or guitar, or drums or mic, or whatever) into the session mode (basically like a spread-sheet full of audio and midi clips). Once recorded, then I go and tidy them up etc, or may tidy each up as I record them. Then I'll often assign a bunch of keys on a keyboard to trigger the clips (like launching phrase on an akai MPC from its pads). Then I can just 'play' the clips from the keyboard and on-the-fly work out and arrangement, maybe assign some knob on a controller to some fx, synth parameters or whatever. Eventually I just hit record and record a complete track on the fly by playing the clips, messing with fx etc. Then go to work on it in a more conventional linear manner like in other DAWs and tidy it up etc.
The nice thing is you stay way more creative I think rather than getting bogged down in the intricacies of using a computer, which personally I find distracting - busy UIs, too much information most of the time, stuff hard to find quickly etc...
I have also used Cubase quite a lot and I do still use it for more conventional linear tracking when need to record things linearly - ie when people know exactly what they are doing - when writing however my experience is that very rarely happens - we get an idea for a section, or in more conventional song term, a chorus, verse, bridge etc and these logically get recorded in live as clips and tidied up so we can play with arrangements very dynamically.
Have a think (and by all means post how you think you would like to work etc) - if Live sounds interesting, you can get a full demo from
http://www.ableton.com. Also it is cross platform, so if you choose to go down the mac route eventually - there is an identical mac version.
There is also a downloadable demo for Sonar (though maybe not the latest version). Steinberg OTOH are a complete pain in the **** and refuse to make a demo version available - so often the only way to try it out is very briefly in a shop or having a mate who uses it. (Perhaps cynically) I think half the reason is so they can sell it on past reputation as these days its so fiddly and messy that unless you know it very well - its quite a horrible thing to get to grips with and a demo TBH would probably put people off.