My first choice for DSLR work is a Sacthler Ace.
A bit above the budget (not that much more than comparable Manfrotto set ups) but the best movements on the head at the price, with handy set drag and variable counterbalance.
(there are two tricks to smooth movements - a properly set up counterbalanced head -take 5 mins at the start of your shoot to achieve this, and setting your position up so that you unwind into a comfortable position at the end of your movement - i.e. don't try and do a smooth ramp to and end position where you are standing on one leg and can't see the viewfinder / lcd. Put your camera in it's end position, stand so your feet are both flat, and set the screen so you can see it without straining. Then go to your start position - this is a trick that actually works! although better heads are better)
If you don;t want to spend as much as on the ACE then you should look at the manfrotto 502HD, it's a little more expensive than the much older 501HDV, but is a far smoother head, it uses fluid rather than teflon discs, and has an easier to set up counterbalance.
The 701 is a toy. No offence to folk who use it, but there are much better heads for not much more money. Counterbalance, set up and position are the keys.
055 legs are ideal, 190 legs are actually okay too if you keep an eye on the max capacity. I prefer these to video legs proper as they tend to have a lower min and higher max height and can be used on uneven terrain much more easily (although the ace comes with a mid level spreader and spiked feet, also quite capable). They are less braced and so more prone to twisting, but with typical SLR loads they will be fine.
Final thing you need for a video tripod is a level base for the tripod head. Dedicated video heads use a bowl. Manfrotto have a couple of modestly priced work arounds, my preferred is the 438 level head, which has a QR level, gives you a decent amount of adjustment and fits between your chosen tripod and head.
If you use a tripod without a bowl or similar then your pans will go wonky, unless you spend a frustrating 10mins setting your tripod up with a spirit level. A bowl -or similar- levels the head in 5 seconds.
Tripods are expensive, but a good tripod, well set up, and the right posture makes a fantastic difference to the quality of your video. A good tripod bought now will be working for you in 20 years. If you buy a cheap tripod you'll bin it and buy a good one anyway.
Best bang per buck:
basic cheapest 055 legs
502HD head (not the bowl one, head only)
A bit more than your budget, not as much as an ACE, but a very decent DSLR tripod set up. Any less than this is so riven with compromises and operational caveats, or just downright poor performance, that it really isn't worth buying.
Read this post in a years time and tell me I'm wrong.
Read it in 10 years and confirm that the slightly more expensive tripod you bought is still working well for you.