Do a search for headsets on these forums - there are lots of opinions about different ones for different aircraft.
From what I know - the headsets you mention are supra-aural (sit on top of your ears, don't enclose them). Neither would be any good for Cessnas/Pipers. If you want a Sennheiser you would need the ANR version of the 25 (I think the HMEC - 25KA), which is very light but probably still too noisy. The best Sennheiser for your needs would be the HME 100, or if you want ANR, the HMEC 350 or 450. These headsets surround your ear and block out a lot of hiss/air noise - which ANR sets don't do very well, and in the case of the 350/450, have ANR as well - good for blocking low frequencies (engine/prop noise).
The Bose is quite good but I found it no good for hiss/air noise, the David Clark X-11 is rubbish (although most other DCs are good) and the Lightspeed Zulu is like the Bose but with bluetooth connection for telephone/MP3 etc. The Telex Stratus 50-D is VERY quiet but heavy and tight on the head.
I found the best all round to be the Sennheiser HMEC-450, however all the ANR sets mentioned cost a lot ($500-$1000), but the passive ones are cheaper (e.g. Sennheiser HME-100 about £200). Most if not all manufacturers or retailers will allow you to return the headsets within about a month for a full refund if you don't like them (which I did with the DC X-11s), and I think Bose will allow you to try them out before buying - but not sure if that covers Latvia!