I have most of the software sims and a GT-100.  (I spent a year deep diving into an HD500 and could never get just a decent plain clean amp sound - sold it - much prefer the GT-100).  Anyway the feel of hardware is always better than any sim at any latency setting IMO.  Having said that I can quickly adapt and it feels fine until I go back to the
GT-100.  The sims are easier to work with and try different sounds.  The GT-001 can re-amp but it's a few more steps.  Good sounds can be had by all.   YMMV

Cactus Music
I spent a few hours in a Music store trying a bunch of hardware sim pedals and amps. I bought the Blackstar ID15 TVP for around $250 Can. I give it 5 stars for tone. 
http://www.sweetwater.com/store/detail/ID15Combo
 
I wanted it originally to see if I could simplify my live rig and pedal board for the rock band I was playing in. I didn't expect it to be so loud on stage! My plan was to just use it at rehearsals and double it up with my beloved Princeton at gigs.  It keeps up as well as any 30 or 40 Watt tube amp I've owned. I soon started leaving the Princeton at home.  It's all worked out perfectly for me and I removed all but 3 must have pedals from my 8 pedal board set up.
 
I didn't buy it for recording but this is actually one of it's strong points. It has a master volume so you can shut the speaker off and just use the stereo line out to the Daw. It has almost totally replaced my old Fender Princeton and after 1 year of gigging and getting banged around is still going strong. 
I bought the Blackstar because out of all I tried that day, it seemed to get "tone" right for me. Of course we all have a different sound in mind but this amp does all of my favorites.  

 
Software-wise, I have S-Gear, GTR Rig 5 and of course the cakewalk offering of TH2/3. I've recorded with all of them several times and like them. If I could only have one, I would choose GTR Rig 5 by a slim margin. They're all decent to impressive.
 
I would be inclined to go with a Helix if I was choosing from one of the big three. With that said, I have a recording pal who has the axe-fx and kemper. He jokingly complains that he can't stop playing the axe-fx once he starts because it sounds so good and is sensible for him to tweak. He likes the kemper a lot, but will part with it at some point. I still use a J-Station. Love that thing! I've had it for so many years that I've found my signature sound more often than not.
 
Piggy backing on Johnny's comments above and a little off topic from the OP.  I was taken back by the nice tones inside of the Blackstar and Peavey Vypyrs amps. It takes a little tweaking, but there are some surprisingly rich and full sounds. I was initially shopping tube amps and surprised myself by buying a Vypyr II.  I know it's appears almost ghetto/cheap go that route, but to that point; for the cost of a couple of pedals these amps are very impressive and worth a listen. They also both offer deeper programing via software, direct USB recording along with direct outs. Not much to not like.
 

wow, the pete thorn vid of the helix is off the charts

I agree about the Pete Thorn video.
He makes everything sound pretty good.   
 
Helix is pretty nice...
Nice for bass too!  There's a Mesa bass amp (forget the model) that I love.

I think the main difference between using an external hardware unit and a software plugin is that you're likely to be recording the guitar 'wet' with a hardware unit (unless you record dry and then use an external fx loop from the DAW, which depends rather on the capabilities of your interface), but you have more ease of flexibility when using a plugin (typically the guitar is always recorded dry then and you can post-record tweak the sound to your heart's content).
 
At the end of the day, the guitar signal is going to be sampled, then maths will be applied to the samples, whether you're talking about a hardware unit or software plugin.
 
If you want to go analog, the SansAmp PSA-1 is very good but expensive.  Too expensive for me when my original broke down, so I went for a Digitech DSP1101 which is somewhat more expensive than the Boss, but very nice indeed.  I use a Rocktron Widowmaker for *clean* sounds; its a solid state analog, pre-amp only (no effects) unit but this would not be my choice for any overdriven or distorted type sounds.
 

The Sansamp Character series are worth investigating. Only one "make" per pedal but they do a pretty good job of capturing the feel and sound. Only thing to watch is the gain controls need winding back a bit from the suggested settings, especially on the British (Marshall) when set to a vintage sound. Like most amp sims these pedals have way more gain on tap than the amps they're emulating, but unlike most digital simulators they can do a pretty good clean and touch-sensitive edge of breakup as well.

 
+1 for the Kemper. Incredible bit of gear.

I have the Eleven Rack and I'm quite pleased with most of the amp models and effects it has to offer.  When I track with this I'll typically record a wet & dry signal to keep options open, but usually do my best to get it right on the first attempt because re-amping is a little more "labor intensive" since you have to mess around with routing as opposed to just slapping a plugin on there. Controlling the Eleven Rack with the editor software is pretty slick.
 
As far as plugins go, I recently jumped on the discounted TH3 upgrade and I'm quite happy with that solution as well. Like Amplitube, TH3 allows for two amp/cab chains in a single setup, so for those who want to get a bit crazy with their rigs, it's more flexible than the Eleven Rack. The drag & drop interface is cool beans.

I am a tube-amp geek. I even build my own so I can get exactly the tone I want.
 
BUT, if I could only afford one amp to do it all, I think it would be a Fender Mustang III amp. You can record direct with it, you can use the Fender Fuse software (bascically IK Amplitude) to record direct to DAW with it, you can use it for a low-volume practice amp, headphones for silent practice, powerful enough to use on-stage unmiked, run it direct to PA... and it won't break your back moving it around or your bank buying it.
 
I use a Mustang I as my practice amp and take it to gigs as my backup. Occasionally I will record with it too. They really do sound very nice.