My advice (and i'd say almost everyone's advice) for a complete beginner would be to get the cheaper 600d. The kit lens 18-55 IS isn't too bad either.
not sure whether this
link will work, but it's comparing the two on the canon website.
not sure how much you've researched, but:
same:
sensor, digic, 63-zone metering (although the 60d uses a smaller 'spot' size), ISO range (although 60d can do 1/3 stop, 600d is 1-stop), vari-lcd screen (although 600d is apparently 'anti-smudge', both take sd-sized cards
different:
60d has better AF (9 cross type vs 1 cross + 8 normal)
60d has top lcd, 600d uses the back screen for reference
60d has pentaprism (better quality), 600d has pentamirror (cheaper/lighter)
60d has a bigger viewfinder (try it out in a shop to see if/how annoying a smaller one is for you)
60d has the electronic level
60d has flash sync to 1/250s, +-3ev comp, 600d to 1/200s, +-2ev comp.
60d does 5.3 fps for 16/58 shots (raw/jpg), 600d does 3.7fps for 6/34 shots.
60d has fullsize raw/mraw/sraw (to save card space), 600d only has fullsize.
60d has weather sealing (at least, to some extent)
60d battery apparently lasts longer (1100 vs 400 shots)
60d is aluminium and polycarbonate (755g), 600d is steel + polycarb (570g)
and it doesn't say it on the canon website, but the 600d can do 1-3x digital zoom when filming (using 'clean' sensor crop), i think up to 10x (using 'dirty' old-school digital zoom).
plus a few small things, like 1/4000s vs 1/8000 shutter speed, interchangeable focussing screens, live-view face detection, more custom functions, data verification kit compatibility may or may not mean anything to you.
ergonomically, the 60d is a fair bit bigger, has a back wheel instead of buttons, and more quick-control buttons on the top near the lcd (the 600d has them doubled with the 4-way buttons on the back)
so which of all that matters? 60D's better AF, weather sealing, more fps for more shots, all those lean towards more action/wildlife.
the lcd and the digital level i find particularly useful, but they're not worth the €300 difference on their own. the bigger viewfinder you'll have to decide yourself if it makes a difference.
And the phrase you'll hear a lot around here is "what do you want to use it for?" if your answer is learning, being creative, filming, street photography, landscapes, travelling light, then all of those point to the 600d.
the only reason to go above that would be for sports/action, not jamming it in your bag at the first sight of rain (but then you need a better lens for full weather sealing), and just a more professional-looking and -handling camera. If you shoot RAW then you don't need any of the gimmiky in-camera effects either way, photoshop what you want later.
ergonomics may also factor. personally, i've got a 7D which has the select wheel and joystick on the back, and dial by the shutter. 60d has the wheel and dial, 600d has 4-way back buttons and the dial.
I'm so used to using the joystick (for selecting af point) and wheel (+-ev in Av mode or shutter speed in M mode) and dial (aperture in Av or M mode), and i can just reach all the buttons by the top lcd with one finger by memory, that i can take almost any picture in any style without even removing my eye from the viewfinder (ok, i've had 10,000 shots of practice).
I tried my sister's 550D the other day, and i couldn't figure out a damn thing. but she's almost as fast as me because she's used to the way her camera is set up. So basically my view ergonomics-wise is that whatever you buy you'll get used to it after a while (just don't buy a better body and downgrade, then you'll notice the difference).
also, another question i'm wondering is what your total budget is. is the 600/900 squid you said with lenses? if i'm spending the same anyway, i'd always go the lower body with more/better lenses and accessories. the niftyfifty (50mm f/1.8 ii) is a 100 euro steal, definitely helps bring out creativity and thoughts about framing and composure rather than just zooming where you want. (also, i'm a nutter for creative photography, research a lensbaby and/or skink pinhole if you really want photos that look different to everyone else).
so there's my (very long) 2c.