I've tried the all-in-one packages like Band In A Box etc but found that as it's all midi none of the backing instruments sound like real instruments - it's more like cheesy lift music. I'd feel daft playing along to it.

What I'm looking for is some software/softwares that will let me create proper sounding backing tracks for me to solo over. I guess it's really just a bassline and a drumtrack. I'd obviously need to be able to specify the key of the bassline and also enter keychanges as required.

I've seen some software I think it's called EZDrummer which looks like it will create the drum track? But no bassline software that lets you specify key-changes.

Are there any packages out there??? Either all-in-one or on their own that could use?

thanks in advance.
fruity loops has built in stuff for basic, decent sounding backing tracks, won't sound real but better than the microsoft wavetable synth (the MIDI sound you are reffering to)
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I use Fruity Loops, but it's not a free program. Any program is as good as the samples you use.
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what about creating the basslines? I'd want to be able to specify the key changes eg. A7 for the first 2 bars, then D7 and so on.

all I really want to do is create say a blues style backing track. simple drums, simple bassline.

maybe it's not possible - the backing tracks I have at the moment have clearly been created in a studio environment with proper instruments.
You might be able to use any of the decent sample-based drum plugins that come with MIDI (BFD, EZ Drummer etc.) and use it with Broomstick Bass which is a plugin that takes chord information and creates basslines in various styles. It just needs some kind of chord input, usually in MIDI format from a keyboard, to do its thing: