Dude, this is a bitcoin forum full of people who are so bullish on btc (and desperate for it), that you're not going to get any answers that are useful. Everybody is going to tell you yes, including myself. I think despite it being at its ATH, it's still worth buying, because the bull market isn't done by a long shot. We'll probably go to $20k or higher by the end of 2018. Don't come back and blame me if it doesn't, though. It's risky as hell but it's made a lot of folks very rich.
Bitcoin will always be good to buy because the best thing is yet to come and for sure in the future bitcoin will become more valuable. Ltc is also great to hold it although its pumping right now and for me better to wait for the correction before you buy it, also make your own study which can help you more on your trading strategy.