well LE is fine, mp3 conversion is not a big issue as you can download loads of freeware progs to do this anyway, cdex for example (if its still around, its been on my pc for an age!)
Cubase has seemed a bit hit and miss for me recently, sx3 was great, 4 seemed like a step backwards but 5 is apparently great (I haven't used it yet). if you can get a cheap copy of sx 3 I'd go for that, great program.
the big hitters are logic, cubase and pro tools, ableton is great, not designed for recording a band but quite capable of doing so, it doesn't have all the features of the other 3 and you don't see it used in any top studios for that reason but its great for home/project studio recording. It also has loads of extra live performance features and audio warpery stuff which is great fun and really useful if you want to do live shows, experimental music or just sync up tracks from different sessions.
pro tools is also great, but le has some really annoying limitations which a lot of the other's don't, they really push for you to buy HD (very expensive) and I dont like that microsoft monopoly thing they have going. That said, for recording a band pro tools has the most fluid and powerful editing/setup I have used.
logic is my normal reccomendation but mac only, annoyingly.
then there are the others, sonar, reaper, digital performer(mac as well) etc.
I havent used these progs very much so I can't comment but there are many happy customers and they seem to be as fully featured as the rest of them. cheaper too in some cases (especially reaper)
what would you mainly be using the software for? recording bands or building tunes from scratch etc?