Did I just go to the wrong bookmark? Could have sworn this was The Escapist, not Bullshido.net...
I've been around martial arts for a while now so I feel I have as much right to say my piece as anyone here. Therefore, at the risk of joining a futile my-art-is-better-than-yours argument (not to mention bruising people's fragile egos) I would like to start by saying that there is no perfect art.
"But what about X? I've been training for y years under Master Z"
No. It's good, but it exists within a specific context and more than likely concentrates on a specific range. If not, you have such an immense curriculum that it takes ages to cover it, much less get good at it (this is he problem I've found with JKD/Kali, especially as there are so many arts added to the basic Jun Fan Gung Fu + Inosanto-Lacoste Blend Kali formula that I doubt any two full instructors in the world have the exact same set of qualifications).
In over a decade of training across 8 different arts (I'm only qualified as an instructor in Inosanto-Lacoste Blend Kali but I continue to train Jun Fan Gung Fu, Muay Thai, Mande Muda Pencak Silat and BJJ with varying degrees of proficiency) there is no "best art", no matter what exponents of varying systems are inclined to tell you.
There are appropriate techniques for different situations. There are attribute building exercises which can increase your ability to perform techniques better. There is the commitment to muscle memory of a group of skills.
Why do I say this and not just toot the horn of the arts which I study or teach? Because I think there are different things which people look for in martial arts and even if you do just want practicality, what does that mean in your life circumstances?
I live in London, in the UK. Gun crime is thankfully low here but there is a continual threat of low-level violence (you are on average 4 times more likely to be attacked in the UK than the US, although statistically the injuries which you are likely to sustain are less serious) and knife crime is still a problem.
I would say for my practical purposes that any art which advocates high kicks is out of the question for practical use because pavements are often wet and slippery and most incidents of attack here involve multiple assailants and occur after drinking.
The same considerations make sections of the Silat or BJJ curricula (as much as I love them and think they're effective styles) impractical in any situation I'm likely to find myself in. Am I going to adopt a harimau stance or take someone into my guard on a wet pavement with his mates crowding round to kick my head in? No. But I might throw them with a puter kapala or an osotogari...
As for Krav Maga, well, I have cross trained with some people who train it (including an ex-IDF guy at my BJJ school) and read some of the books on it (not to mention the countless videos on youtube) and whilst there is some good commonsense stuff there, a lot of the time I've been unconvinced (particularly their ideas about knife defence- trying to keep the person away with your feet whilst protecting your body with the hands sounds good until you realise that you're giving your attacker a clear shot at your femoral artery every time you do it).
I don't mean to dismiss it out of hand- Imi Sde-Or was a tough SOB and he used wrestling and boxing to make a powerful no-holds-barred system. I just think the awe in which people hold it is a little too much. "Wow, it was like, developed by the Israeli Army!" So what? They think air-strikes are a measured way to take out paraplegics.
Ditto Systema. Again, interesting concept, taking Russian Sambo/Judo and mixing with striking and a lot of pressure testing- this is good. The aura of fear and mystique is horseshit. Ultimately if you have a hench guy with good technique and fitness he is going to do well whatever he's trained in. The Spetznaz are no exception.
As for the MMA-is-the-best camp, well, they're half-right. You DO have to take different elements from different styles and make them gel to create something seamless, making sure that you can work in different ranges and reducing your vulnerability to various techniques.
Unfortunately, since about UFC 10 or so, the general rules for MMA forbid so many techniques that what is allowed is very much a sport form. Not to say that it isn't a brutal and dangerous sport- I wouldn't want to fight someone who was doing MMA professionally because they'd be a hell of a lot fitter than me and probably train the techniques they train as many hours in a day as I do in a week. Notice how the MMA circuit is mainly Muay Thai and BJJ? That's because they're sport forms. Eye-gouges, groin strikes and all that other street-practical stuff we love is already banned, so the athletes don't train it or train to protect against it. Nor do they train against weapon attacks- no-one has ever gone into the Octagon with a machete and started cutting bits out of their opponent.
In answer to the question of what the most practical art would be I would have to say that it depends on your circumstances, but you should cover ranges at least from kicking to punching to trapping, standing grappling and ground-fighting. If you live in a place where guns are a likely threat, look at that range too. Shop around. Absorb what is useful and discard what isn't.
Don't be afraid to ask questions (humbly and politely of course) about techniques you've learnt in one class elsewhere when you can get the instructor to yourself. If you're in a good place you may test their patience if you do this a lot, but they should have a thoughtful answer free from pseudo-mystical B.S. If you can never get the instructor to yourself and you walk up and down a hall doing kata all class, seriously reconsider where you've chosen to train.
Right, I'm off to train. Have fun, train hard and don't let ego get in the way of learning.