I cannot advocate any alt coins for 2015. But I can look at the historical data each coin presents, research its community and then invest in a few chosen ones, with my own home-made trading method.
The very first thing I do, is look at coinmarketcap.com, for the latest and greatest alt coin data.
On coinmarketcap, I always look for coins with the following criteria:
-- Relatively high 24 hour volume
-- Good volatility on price chart (x.5 to x3 value change) for 30-90 days
-- Lower entry price point ($0.0000x to $0.0x) for maximum shares
-- Is coin accessible on popular exchanges, ones you have access to?
-- No instamine or premine if possible (rare)
-- (Tip: you can sort coinmarket data columns by price, volume, etc)
After finding coins with above criteria, I do more research to see if a coin:
-- Has competent trustworthy developer(s) (Does the wallet work?)
-- Has any outstanding, innovative feature(s)
-- Is actively supported by the mining community
-- (Hint: research the above on coin's main Bitcointalk thread or its own forum)
After winnowing my choices, I pick the best 2-3 coins and invest using my homegrown trading method.
(Hollingsworth Method)
Good luck!!
H.