Of the three bikes you've shortlisted, the Triumph Scrambler 400 X will be the best all-rounder and will also be very easy to ride inside city traffic with its tractable engine and short gearing. 

While the RTX 300 has slightly better suspension travel and composure, it is still a new product, and it would be advisable to wait some months before buying an all-new machine like this, so if there are any teething issues, they can be ironed out. 

If you are open to having a retro riding experience, then the Royal Enfield Bullet / Classic 350 are worth looking at. These are very comfortable machines, although their performance won't be anywhere close to as sprightly as the other bikes you're looking at. 

On the plus side, the Bullet/Classic are much more affordable to purchase. 

We'd recommend a test ride of the RE 350s before you make a decision. 

Since you haven't specified what style of bike you want, nor given some details about your physique, recommending something concrete will not be possible. However, we'll give you a variety of options to choose from, spanning multiple classes. 

In the neo-retro space, you can look at bikes like the Royal Enfield Classic / Bullet / Hunter 350, TVS Ronin, Triumph Speed T4 and Honda CB350 models. These will have a relaxed riding experience and a plush, comfortable ride quality. The Speed T4 will be the quickest and most responsive of them all, but still very manageable for daily use.

If you want something sportier, the KTM 250 Duke makes for a compelling option for your one-bike garage. 

If you're leaning towards the more adventurous side of things, then the Hero Xpulse 210 and the TVS Apache RTX 300 are the way to go. 

It would be advisable to take test rides of all of these bikes to see what style you prefer and which bike you are most comfortable with. 

The Battalion Black is the base variant in the Royal Enfield Bullet 350 lineup and has a simpler finish for certain components and only single-channel ABS owing to its rear drum brake. However, its riding experience should largely be the same as the other variants, and in that sense, it would make for a relaxed, characterful and comfortable motorcycle. 

In many ways, the Honda CB350RS will feel similiar to ride because of its air-cooled engine and plush suspension. But it has a sportier, more engaging seating position and feels a lot lighter on its feet. It also comes with modern conveniences such as tubeless tyres, a slip/assist clutch and all-LED lighting. The CB350RS is also over Rs 30,000 more expensive than the Bullet 350 Battalion Black, so price will play a key role in your purchase decision. 

Picking between the two will boil down to which bike you gel with better. Also, whether you think the Honda deserves the extra money it commands over the Royal Enfield. 

In the 350cc space, bikes like the Royal Enfield Hunter / Classic / Bullet 350 and Honda CB350 trio make for good options considering your mixed usage. All of them have upright ergonomics, comfortable suspension setups and decent fuel economy. 

If you are open to waiting for a few months, Bajaj will be releasing 350cc versions of all the Triumph 400cc bikes. These will offer you noticeably more performance than the aforementioned air-cooled 350s while being priced similarly.