If you're willing to wait a little while, I would say do that. 
 
You will be getting more and wont have to get the game again if you decide to get SSF4.

if you really, really want it, go ahead and buy it. it's at a reasonable price now (and i think super SFIV will be at a reduced price) 

if you wait then you won't have the skill needed to really compete. even though this game will become outdated, you will still learn theory and strategy that can be applied anywhere.

You can get the best current gen fighting game for $20 (obligatory my opinion here), why not? You may as well learn the game if you are going to get into SSFIV later.

I say go for it.  It's only $30 new now and defiantly well worth it.  Super Street Fighter IV wont be coming out for like 4 to 6 months so, SFIV should help you for the time being.

Get it to learn SFIV, and if you get the 360 version, there's a good number of Giantbomb users to play.

I've seen it at Wal Mart and Target for like $20. Its a very reasonable price. I'd say buy it now.

" if you wait then you won't have the skill needed to really compete. even though this game will become outdated, you will still learn theory and strategy that can be applied anywhere. "

I would suggest waiting. But it really depends if you want to be able to compete online at the release of SSFIV or if you don't mind losing a lot for a little bit. Well, either way you will probably lose a lot at first it since you're just learning. Although SSFIV will have more to learn than if you start with SFIV. So if you do get SFIV you will at least know the basics by the time SSFIV comes out.

i say wait. but realize that no matter what, you will lose eventually. Nobody wins forever

" I say go for it.  It's only $30 new now and defiantly well worth it.  Super Street Fighter IV wont be coming out for like 4 to 6 months so, SFIV should help you for the time being. "

Obviously get it, SSFIV will be very similar, read: identical to SFIV, as its mainly new characters and balance tweaks.  
You'll learn focus attacks, FADC's, and SF basics like zoning and knowing how to punish. Otherwise when SSFIV comes out you'll be one of the scrubs getting raped by people who have played before ;)

*obligatory Atlas likes Virtua Fighter more than Street Fighter post*
 
Seriously, though, if you're interested in a Street Fighter game, just get SFIV. It's a good deal right now, and a lot of people have had some extremely nice things to say about that game. Never pass up the opportunity to get a great game at a great chance.
 
Or you could get Virtua Fighter 5. That's even cheaper. And, you know, better.

" *obligatory Atlas likes Virtua Fighter more than Street Fighter post*  Seriously, though, if you're interested in a Street Fighter game, just get SFIV. It's a good deal right now, and a lot of people have had some extremely nice things to say about that game. Never pass up the opportunity to get a great game at a great chance.  Or you could get Virtua Fighter 5. That's even cheaper. And, you know, better. "

If you're competitive get it now.

" *obligatory Atlas likes Virtua Fighter more than Street Fighter post*  Seriously, though, if you're interested in a Street Fighter game, just get SFIV. It's a good deal right now, and a lot of people have had some extremely nice things to say about that game. Never pass up the opportunity to get a great game at a great chance.  Or you could get Virtua Fighter 5. That's even cheaper. And, you know, better. "

I'll echo the earlier sentiments: it's super cheap, a must-own game and you'll have a few months of fun while honing your skills before the next iteration is out. 
 
Also, does anyone know if the storylines/campaigns from the original will be in Super? If not, then there's that going for a buy-now as well.

Along with what everyone else said, you supposedly also get some sort of bonus in SSFIV if you own SFIV.

" @Asurastrike: what the hell do you mean? its very simple, play against alot of people and youy will get better reguardless of which game you're playing. many mindgames and tactics go across different games in the genre. so much of what you learn in SF$ will work just fine in SSF4. do you not get the idea or are you just retarded as such? "

" @Asurastrike: that is a terrible thing to hate. what logic is there behind it?  id say get it, you can find it for 19.99 at some places and it won't be another 5 months (i think march at earliest, make it little over a year) till SSIV comes out. And 5 months of fun and practice is going to be hugely beneficial, especially if you plan to enjoy the higher levels of play once the update comes out. Everyone who's bought SF4 is going to buy SS4 (unless theyre not fans of the genre) and you're damn right theyve been practicing for over a year. "

I'm waiting, because I know I'm almost definitely buying the super version

SF4 is actually not that difficult for noobs. Well, I say that, but only because bitches don't know bout IIIstrike.
 
I'd say get it. It's gonna be a while before SSF4 appears, and you should get the practice in. Also, I think people who own both will get a bonus in SSF4. So, why not. You can always sell it to make up a bit of the price later on.

" @Asurastrike: You are getting mad at how a person spends his time? Frankly, fuck you. You can do whatever you want with your time, but don't go around telling other people that the hobbies they may enjoy aren't worth the time. Do you spend every waking moment doing useful stuff? "

" @Asurastrike: care about this thread at all? man we should really put an iq test to get onto this internet thing of ours "

If you get it I'll help teach you how to play.

" If you get it I'll help teach you how to play. "

Wait for the game but get HYPE